diff --git a/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no0001/Solution.java b/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no0001/Solution.java
new file mode 100644
index 00000000..f8bd31b3
--- /dev/null
+++ b/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no0001/Solution.java
@@ -0,0 +1,43 @@
+package cn.iocoder.springboot.labs.lab09.leetcode.no0001;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+
+class Solution {
+
+//    public int[] twoSum(int[] nums, int target) {
+//        for (int i = 0; i < nums.length; i++) {
+//            for (int j = i + 1; j < nums.length; j++) {
+//                int sum = nums[i] + nums[j];
+//                if (sum == target) {
+//                    return new int[]{i, j};
+//                }
+//            }
+//        }
+//        return new int[]{0};
+//    }
+
+    public int[] twoSum(int[] nums, int target) {
+        Map<Integer, Integer> numMap = new HashMap<>(nums.length, 1.0F);
+        for (int i = 0; i < nums.length; i++) {
+            // 避免相同数字相加，恰好相等
+            Integer j = numMap.get(target - nums[i]);
+            if (j != null) {
+                return new int[]{j, i};
+            }
+            numMap.put(nums[i], i);
+        }
+        return new int[]{0};
+    }
+
+    public static void main(String[] args) {
+//        int[] result = new Solution().twoSum(new int[]{0, 4, 3, 0}, 0);
+//        System.out.println(Arrays.toString(result));
+        int[] result = new Solution().twoSum(new int[]{2, 7, 11, 15}, 9);
+        System.out.println(Arrays.toString(result));
+//        int[] result = new Solution().twoSum(new int[]{-1, -2, -3, -4, -5}, -8);
+//        System.out.println(Arrays.toString(result));
+    }
+
+}
diff --git a/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no0015/Solution.java b/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no0015/Solution.java
new file mode 100644
index 00000000..e3376261
--- /dev/null
+++ b/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no0015/Solution.java
@@ -0,0 +1,107 @@
+package cn.iocoder.springboot.labs.lab09.leetcode.no0015;
+
+import java.util.*;
+
+class Solution {
+
+    public List<List<Integer>> threeSum(int[] nums) {
+        // 排序
+        Arrays.sort(nums);
+
+        // 获得结果
+        List<List<Integer>> results = new ArrayList<>();
+        for (int i = 0; i < nums.length - 2; i++) {
+            if (i > 0 && nums[i] == nums[i - 1]) {
+                continue;
+            }
+            int target = -nums[i];
+            // 遍历
+            int start = i + 1, end = nums.length - 1;
+            while (start < end) {
+                // 符合条件
+                int sum = nums[start] + nums[end];
+                if (sum == target) {
+                    // 添加到结果
+                    results.add(Arrays.asList(nums[i], nums[start], nums[end]));
+                    // 增大 start
+                    do {
+                        start++;
+                    } while (nums[start] == nums[start - 1] && start < end);
+                    // 减小 end
+                    do {
+                        end--;
+                    } while (nums[end] == nums[end + 1] && start < end);
+                    continue;
+                }
+                // 小于预期，说明 start 对应的值太小，start 继续前进。
+                if (sum < target) {
+                    do {
+                        start++;
+                    } while (nums[start] == nums[start - 1] && start < end);
+                // 大于预期，说明 end 对应的值太大，end 继续后退
+                } else {
+                    do {
+                        end--;
+                    } while (nums[end] == nums[end + 1] && start < end);
+                }
+            }
+        }
+
+        return results;
+    }
+
+    public List<List<Integer>> convert(Set<List<Integer>> result) {
+        List<List<Integer>> newResult = new ArrayList<>(result.size());
+        newResult.addAll(result);
+        return newResult;
+    }
+
+    private List<List<Integer>> removeSome(List<List<Integer>> results) {
+        // 排序
+        for (List<Integer> result : results) {
+            Collections.sort(result);
+        }
+        // 移除重复的
+        List<List<Integer>> newResults = new ArrayList<>();
+        for (List<Integer> result : results) {
+            boolean exists = false;
+            for (List<Integer> targetResult : newResults) {
+                if (targetResult.equals(result)) {
+                    exists = true;
+                    break;
+                }
+            }
+            if (!exists) {
+                newResults.add(result);
+            }
+        }
+        return newResults;
+    }
+
+//    public int[] twoSum(int[] nums, int start, int target) {
+//        Map<Integer, Integer> numMap = new HashMap<>(nums.length, 1.0F);
+//        for (int i = start; i < nums.length; i++) {
+//            numMap.put(nums[i], i);
+//        }
+//        for (int i = start; i < nums.length; i++) {
+//            // 避免相同数字相加，恰好相等
+//            Integer j = numMap.get(target - nums[i]);
+//            if (j != null) {
+//                if (j == i) {
+//                    continue;
+//                }
+//                return new int[]{i, j};
+//            }
+//        }
+//        return new int[]{0};
+//    }
+
+    public static void main(String[] args) {
+//        System.out.println(new Solution().threeSum(new int[]{-1, 0, 1, 2, -1, -4}));
+//        System.out.println(new Solution().threeSum(new int[]{0,0,0,0}));
+//        System.out.println(new Solution().threeSum(new int[]{-2, 0, 1, 1, 2}));
+        System.out.println(new Solution().threeSum(new int[]{1,-1,-1,0}));
+//        System.out.println(new Solution().threeSum(new int[]{-7,-11,12,-15,14,4,4,11,-11,2,-8,5,8,14,0,3,2,3,-3,-15,-2,3,6,1,2,8,-5,-7,3,1,8,11,-3,6,3,-4,-13,-15,14,-8,2,-8,4,-13,13,11,5,0,0,9,-8,5,-2,14,-9,-15,-1,-6,-15,9,10,9,-2,-8,-8,-14,-5,-14,-14,-6,-15,-5,-7,5,-11,14,-7,2,-9,0,-4,-1,-9,9,-10,-11,1,-4,-2,2,-9,-15,-12,-4,-8,-5,-11,-6,-4,-9,-4,-3,-7,4,9,-2,-5,-13,7,2,-5,-12,-14,1,13,-9,-3,-9,2,3,8,0,3}));
+    }
+
+}
diff --git a/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no0020/Solution.java b/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no0020/Solution.java
new file mode 100644
index 00000000..7b259244
--- /dev/null
+++ b/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no0020/Solution.java
@@ -0,0 +1,43 @@
+package cn.iocoder.springboot.labs.lab09.leetcode.no0020;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Solution {
+
+    public boolean isValid(String s) {
+        List<Character> array = new ArrayList<>();
+        for (int i = 0; i < s.length(); i++) {
+            char ch = s.charAt(i);
+            if (ch == '('
+                || ch == '{'
+                || ch == '[') {
+                array.add(ch);
+            } else {
+                if (array.isEmpty()) {
+                    return false;
+                }
+                int arrayCh = array.get(array.size() - 1);
+                if ((arrayCh == '(' && ch == ')')
+                    || (arrayCh == '{' && ch == '}')
+                    || (arrayCh == '[' && ch == ']')) {
+                    array.remove(array.size() - 1);
+                } else {
+                    return false;
+                }
+            }
+        }
+        return array.isEmpty();
+    }
+
+    public static void main(String[] args) {
+        System.out.println(new Solution().isValid("()"));
+        System.out.println(new Solution().isValid("()[]{}"));
+        System.out.println(new Solution().isValid("(]"));
+        System.out.println(new Solution().isValid("([)]"));
+        System.out.println(new Solution().isValid("{[]}"));
+        System.out.println(new Solution().isValid("["));
+        System.out.println(new Solution().isValid("]"));
+    }
+
+}
diff --git a/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no0025/ListNode.java b/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no0025/ListNode.java
new file mode 100644
index 00000000..413afeef
--- /dev/null
+++ b/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no0025/ListNode.java
@@ -0,0 +1,17 @@
+package cn.iocoder.springboot.labs.lab09.leetcode.no0025;
+
+class ListNode {
+    int val;
+    ListNode next;
+    ListNode(int x) {
+        val = x;
+        next = null;
+    }
+
+    @Override
+    public String toString() {
+        return "ListNode{" +
+                "val=" + val +
+                '}';
+    }
+}
diff --git a/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no0025/Solution.java b/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no0025/Solution.java
new file mode 100644
index 00000000..99f2310b
--- /dev/null
+++ b/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no0025/Solution.java
@@ -0,0 +1,93 @@
+package cn.iocoder.springboot.labs.lab09.leetcode.no0025;
+
+class Solution {
+    private ListNode swap(ListNode first, ListNode head, ListNode last) {
+        ListNode originCurrent = head;
+
+        // 先设置 first 指向 last
+//        if (first != null) {
+//            first.next = last;
+//        }
+
+        // 进行反序
+        ListNode newHead = null;
+        ListNode tail = last.next; // 用于判断结尾
+        while (head != tail) {
+            ListNode current = head;
+            head = head.next;
+            // 反向指向
+            current.next = newHead;
+            newHead = current;
+        }
+
+        // 原始的头，指向 tail
+        originCurrent.next = tail;
+
+        // first 指向新的头
+        if (first != null) {
+            first.next = newHead;
+        }
+
+        // 返回结果
+        return newHead;
+    }
+
+    public ListNode reverseKGroup(ListNode head, int k) {
+        if (head == null) {
+            return null;
+        }
+        ListNode tmp = head;
+
+        ListNode first = null; // 记录每个 N 个一组的前一个节点。
+        ListNode current = head; // 记录 N 组的头节点。
+        ListNode newHead = null; // 因为反转，所以可能产生新的头
+        int counts = 0; // 计数 N
+        while (tmp != null) {
+            // 每 N 个形成一组，进行交换。
+            counts++;
+            if (counts == k) {
+                ListNode tail = tmp.next;
+                ListNode result = swap(first, current, tmp);
+                if (newHead == null) { // 第一次反转的结果，成为新的头。
+                    newHead = result;
+                }
+                counts = 0;
+                // 设置下一组
+                first = current;
+                current = tail;
+                tmp = tail;
+            } else {
+                // 跳到下一个节点
+                tmp = tmp.next;
+            }
+        }
+
+        return newHead != null ? newHead : head;
+    }
+
+    public static void main(String[] args) {
+        if (false) {
+            ListNode head = new ListNode(1);
+            int[] values = new int[]{2, 3, 4, 5};
+            ListNode current = head;
+            for (int value : values) {
+                current.next = new ListNode(value);
+                current = current.next;
+            }
+            ListNode result = new Solution().reverseKGroup(head, 3);
+            System.out.println(result);
+        }
+        if (true) {
+            ListNode head = new ListNode(1);
+            int[] values = new int[]{2, 3, 4};
+            ListNode current = head;
+            for (int value : values) {
+                current.next = new ListNode(value);
+                current = current.next;
+            }
+            ListNode result = new Solution().reverseKGroup(head, 2);
+            System.out.println(result);
+        }
+    }
+
+}
diff --git a/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no0142/ListNode.java b/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no0142/ListNode.java
new file mode 100644
index 00000000..05b9cc54
--- /dev/null
+++ b/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no0142/ListNode.java
@@ -0,0 +1,17 @@
+package cn.iocoder.springboot.labs.lab09.leetcode.no0142;
+
+class ListNode {
+    int val;
+    ListNode next;
+    ListNode(int x) {
+        val = x;
+        next = null;
+    }
+
+    @Override
+    public String toString() {
+        return "ListNode{" +
+                "val=" + val +
+                '}';
+    }
+}
diff --git a/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no0142/Solution.java b/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no0142/Solution.java
new file mode 100644
index 00000000..aa463bd8
--- /dev/null
+++ b/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no0142/Solution.java
@@ -0,0 +1,135 @@
+package cn.iocoder.springboot.labs.lab09.leetcode.no0142;
+
+import java.util.HashSet;
+import java.util.Set;
+
+public class Solution {
+
+    /**
+     * 性能较差
+     *
+     * 每次走到下一个节点，都从头节点重新遍历，看看有没回环。
+     *
+     * @param head 头节点
+     * @return 回环的点
+     */
+    public ListNode detectCycle01(ListNode head) {
+        if (head == null) {
+            return null;
+        }
+        // 寻找结尾
+        ListNode current = head;
+        while (current.next != null) {
+            ListNode oldCurrent = current;
+            ListNode tmpHead = head;
+            // 跳到下一个
+            current = current.next;
+            // 处理，自己指向自己的情况
+            if (current == oldCurrent) {
+                return current;
+            }
+            // 从头结点开始走，判断是否有回环
+            while (tmpHead != null) {
+                //
+                if (tmpHead == oldCurrent) {
+                    break;
+                }
+                if (tmpHead == current) {
+                    return current;
+                }
+                tmpHead = tmpHead.next;
+            }
+        }
+        return null;
+    }
+
+    public ListNode detectCycle02(ListNode head) {
+        if (head == null) {
+            return null;
+        }
+        Set<ListNode> visited = new HashSet<>();
+        while (head != null && head.next != null) {
+            visited.add(head);
+            if (visited.contains(head.next)) {
+                return head.next;
+            }
+            head = head.next;
+        }
+        return null;
+    }
+
+    private ListNode getIntersect(ListNode head) {
+        ListNode slow = head;
+        ListNode fast = head;
+        while (fast != null && fast.next != null) {
+            slow = slow.next;
+            fast = fast.next.next;
+            if (slow == fast) {
+                return slow;
+            }
+        }
+        return null;
+    }
+
+    public ListNode  detectCycle03(ListNode head) {
+        if (head == null) {
+            return null;
+        }
+
+        // 先使用快慢指针，找到想交的节点
+        ListNode intersect = getIntersect(head);
+        if (intersect == null) { // 如果为空，说明不存在环
+            return null;
+        }
+
+        // 找到环的入口
+        ListNode ptr1 = head;
+        ListNode ptr2 = intersect;
+        while (ptr1 != ptr2) {
+            ptr1 = ptr1.next;
+            ptr2 = ptr2.next;
+        }
+
+        return ptr1;
+    }
+
+    public ListNode detectCycle(ListNode head) {
+//        return detectCycle01(head);
+//        return detectCycle02(head);
+        return detectCycle03(head);
+    }
+
+    public static void main(String[] args) {
+        if (true) {
+            ListNode head = new ListNode(1);
+            ListNode tail = new ListNode(2);
+            head.next = tail;
+            tail.next = head;
+            System.out.println(new Solution().detectCycle(head));
+        }
+        if (false) {
+            ListNode head = new ListNode(1);
+            head.next = head;
+            System.out.println(new Solution().detectCycle(head));
+        }
+        if (false) {
+            ListNode head = new ListNode(1);
+            ListNode tail = new ListNode(2);
+            head.next = tail;
+            tail.next = tail;
+            System.out.println(new Solution().detectCycle(head));
+        }
+        if (false) {
+            ListNode head = new ListNode(1);
+            ListNode tail = new ListNode(2);
+            ListNode second = new ListNode(3);
+            head.next = second;
+            second.next = tail;
+            tail.next = second;
+            ListNode result = new Solution().detectCycle(head);
+//            System.out.println();
+            assert result == second;
+        }
+    }
+
+}
diff --git a/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no0242/Solution.java b/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no0242/Solution.java
new file mode 100644
index 00000000..f3110a44
--- /dev/null
+++ b/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no0242/Solution.java
@@ -0,0 +1,45 @@
+package cn.iocoder.springboot.labs.lab09.leetcode.no0242;
+
+import java.util.HashMap;
+import java.util.Map;
+
+class Solution {
+
+    public boolean isAnagram(String s, String t) {
+        if (s == null || t == null) {
+            return false;
+        }
+        if (s.length() != t.length()) {
+            return false;
+        }
+        // 创建 s 使用的哈希表
+        Map<Character, Integer> map = new HashMap<>();
+        for (char ch : s.toCharArray()) {
+            Integer counts = map.get(ch);
+            counts = counts != null ? counts + 1 : 1;
+            map.put(ch, counts);
+        }
+        // 判断 t 是否有
+        for (char ch : t.toCharArray()) {
+           Integer counts = map.get(ch);
+           if (counts == null) {
+               return false;
+           }
+           counts--;
+           if (counts == 0) {
+               map.remove(ch);
+           } else {
+               map.put(ch, counts);
+           }
+        }
+        return true;
+    }
+
+    public static void main(String[] args) {
+        Solution solution = new Solution();
+        System.out.println(solution.isAnagram("anagram", "nagaram"));
+        System.out.println(solution.isAnagram("rat", "cat"));
+        System.out.println(solution.isAnagram("ccac", "aacc"));
+    }
+
+}
diff --git a/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no039/Solution.java b/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no039/Solution.java
new file mode 100644
index 00000000..104c42be
--- /dev/null
+++ b/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no039/Solution.java
@@ -0,0 +1,104 @@
+package cn.iocoder.springboot.labs.lab09.leetcode.no039;
+
+import java.util.*;
+
+public class Solution {
+
+    class Node {
+
+        public int index;
+
+        public int value;
+
+        public Node(int index, int value) {
+            this.index = index;
+            this.value = value;
+        }
+
+    }
+
+    public int[] maxSlidingWindow(int[] nums, int k) {
+        List<Node> queue = new LinkedList<>();
+        List<Integer> result = new ArrayList<>(nums.length - k + 1);
+        for (int i = 0; i < nums.length; i++) {
+            int maxValue = Integer.MIN_VALUE;
+            if (!queue.isEmpty()) {
+                // 移除超过范围的节点
+                if (queue.get(0).index == i - k) {
+                    queue.remove(0);
+                }
+                // 移除队列中，小于当前位置的元素
+                ListIterator<Node> listiterator = queue.listIterator(queue.size()); // 倒序向前
+                while (listiterator.hasPrevious()) {
+                    Node node = listiterator.previous();
+                    if (nums[i] >= node.value) {
+                        listiterator.remove();
+                    } else {
+                        maxValue = node.value; // 说明，此值更大
+                    }
+                }
+            }
+            // 判断是否有更大的
+            if (nums[i] > maxValue) {
+                maxValue = nums[i];
+            }
+            // 添加到队尾
+            queue.add(new Node(i, nums[i]));
+            // 添加到结果
+            if (i >= k -1) {
+                result.add(maxValue);
+            }
+        }
+        return result.stream().mapToInt(i -> i).toArray();
+    }
+
+//    public int[] maxSlidingWindow(int[] nums, int k) {
+//        int[] num = nums;
+//        int size = k;
+//        //num就是nums，size就是k，res一开始也可以用数组
+//        ArrayList<Integer> res = new ArrayList<>();
+//        if(num == null || num.length == 0 || size <= 0 || size > num.length){
+//            return res.stream().mapToInt(i -> i).toArray();
+//        }
+//        int left = 0, right = 0, max = num[0];
+//        while(right < num.length){
+//            while(right < num.length-1 && right - left < size-1){
+//                right++;
+//                if(num[right] > max){
+//                    max = num[right];
+//                }
+//            }
+//            res.add(max);
+//            left++;
+//            if(right == num.length-1) break;
+//            if(num[left-1] == max){
+//                right = left;
+//                max = num[left];
+//            }
+//        }
+//        return res.stream().mapToInt(i -> i).toArray();
+//    }
+
+    public static void main(String[] args) {
+        if (false) {
+            int[] nums = {1, 3, -1, -3, 5, 3, 6, 7};
+            int k = 3;
+            int[] result = new Solution().maxSlidingWindow(nums, k);
+            System.out.println(Arrays.toString(result));
+        }
+        if (true) {
+            int[] nums = {1, 3, 1, 2, 0, 5};
+            int k = 3;
+            int[] result = new Solution().maxSlidingWindow(nums, k);
+            System.out.println(Arrays.toString(result));
+        }
+    }
+
+//    private static void println(List<Node> queue) {
+//        for (Node node : queue) {
+//            System.out.print(" " + node.value);
+//        }
+//        System.out.println();
+//    }
+
+}
diff --git a/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no0703/KthLargest.java b/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no0703/KthLargest.java
new file mode 100644
index 00000000..15e1e93e
--- /dev/null
+++ b/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no0703/KthLargest.java
@@ -0,0 +1,136 @@
+package cn.iocoder.springboot.labs.lab09.leetcode.no0703;
+
+class KthLargest {
+
+    /**
+     * 小顶堆
+     */
+    private int[] heap;
+    /**
+     * 堆的位置
+     */
+    private int heapIndex;
+    private int k;
+
+    public KthLargest(int k, int[] nums) {
+        this.heap = new int[k + 1];
+        this.heapIndex = 1;
+        this.k = k;
+        // 初始化
+        for (int num : nums) {
+            add(num);
+        }
+    }
+
+    public int add(int val) {
+        if (heapIndex <= k) {
+            // 赋值
+            heap[heapIndex] = val;
+            heapIndex++;
+
+            // 向上堆化
+            heapifyUp(heapIndex - 1);
+        } else {
+            if (val > heap[1]) { // 大于最小值，才有资格加入其中。因为我们构建的 heap 是小顶堆，最上面存储的是第 k 大。
+                // 赋值
+                heap[1] = val;
+
+                heapifyDown(1);
+            }
+        }
+
+        return heap[1];
+    }
+
+//    private int remove0() {
+//        // 取头元素
+//        int val = heap[1];
+//
+//        // 将尾巴设置到头
+//        heap[1] = heap[heapIndex - 1];
+//        heapIndex--;
+//
+//        // 向下堆化
+//        heapifyDown(1);
+//
+//        return val;
+//    }
+
+    public void heapifyUp(int index) {
+        while (index > 1) { // 注意，此处要大于 1
+            int parent = index / 2;
+            if (heap[index] < heap[parent]) {
+                swap(index, parent);
+                index = parent;
+            } else {
+                break;
+            }
+        }
+    }
+
+    private void heapifyDown(int index) {
+        while (true) {
+            int pos = index;
+            // 求子节点中，哪个
+            if (index * 2 < heapIndex && heap[index * 2] < heap[index]) {
+                pos = index * 2;
+            }
+            if (index * 2 + 1 < heapIndex && heap[index * 2 + 1] < heap[pos]) {
+                pos = index * 2 + 1;
+            }
+            // 如果毫无变化，说明已经不需要继续向下
+            if (pos == index) {
+                return;
+            }
+            // 交换
+            swap(index, pos);
+            index = pos;
+        }
+    }
+
+    private void swap(int i, int j) {
+        int tmp = heap[i];
+        heap[i] = heap[j];
+        heap[j] = tmp;
+    }
+
+//    private int findMaxValueIndex() {
+//        int max = Integer.MIN_VALUE;
+//        int maxIndex = -1;
+//        for (int i = log2(heapIndex) * 2; i < heapIndex; i++) { // 从 log2(heapIndex) * 2 的原因是，从叶子节点开始。因为我们构建的是小顶堆，那么最大值必定在叶子节点上。
+//            if (heap[i] > max) {
+//                max = heap[i];
+//                maxIndex = i;
+//            }
+//        }
+//        return maxIndex;
+//    }
+//
+//    private static int log2(int x) {
+//        return (int) (Math.log(x) / Math.log(2));
+//    }
+
+    public static void main(String[] args) {
+        if (false) {
+            int k = 3;
+            int[] nums = {4, 5, 8, 2};
+            KthLargest kthLargest = new KthLargest(k, nums);
+            System.out.println(kthLargest.add(3));
+            System.out.println(kthLargest.add(5));
+            System.out.println(kthLargest.add(10));
+            System.out.println(kthLargest.add(9));
+            System.out.println(kthLargest.add(4));
+        }
+        if (true) {
+            int k = 1;
+            int[] nums = {};
+            KthLargest kthLargest = new KthLargest(k, nums);
+            System.out.println(kthLargest.add(-3));
+            System.out.println(kthLargest.add(-2));
+            System.out.println(kthLargest.add(-4));
+            System.out.println(kthLargest.add(0));
+            System.out.println(kthLargest.add(4));
+        }
+    }
+
+}
diff --git a/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no0703/KthLargest2.java b/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no0703/KthLargest2.java
new file mode 100644
index 00000000..e49da2a0
--- /dev/null
+++ b/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/no0703/KthLargest2.java
@@ -0,0 +1,57 @@
+package cn.iocoder.springboot.labs.lab09.leetcode.no0703;
+
+import java.util.PriorityQueue;
+import java.util.Queue;
+
+class KthLargest2 {
+
+    private Queue<Integer> queue;
+    private int k;
+
+    public KthLargest2(int k, int[] nums) {
+        queue = new PriorityQueue<>(k);
+        this.k = k;
+        // 初始化
+        for (int num : nums) {
+            add(num);
+        }
+    }
+
+    public int add(int val) {
+        if (queue.size() < k) {
+            // 赋值
+            queue.add(val);
+        } else {
+            if (val > queue.peek()) { // 大于最小值，才有资格加入其中。因为我们构建的 heap 是小顶堆，最上面存储的是第 k 大。
+                queue.poll();
+                queue.add(val);
+            }
+        }
+
+        return queue.peek();
+    }
+
+    public static void main(String[] args) {
+        if (true) {
+            int k = 3;
+            int[] nums = {4, 5, 8, 2};
+            KthLargest2 kthLargest = new KthLargest2(k, nums);
+            System.out.println(kthLargest.add(3));
+            System.out.println(kthLargest.add(5));
+            System.out.println(kthLargest.add(10));
+            System.out.println(kthLargest.add(9));
+            System.out.println(kthLargest.add(4));
+        }
+        if (false) {
+            int k = 1;
+            int[] nums = {};
+            KthLargest2 kthLargest = new KthLargest2(k, nums);
+            System.out.println(kthLargest.add(-3));
+            System.out.println(kthLargest.add(-2));
+            System.out.println(kthLargest.add(-4));
+            System.out.println(kthLargest.add(0));
+            System.out.println(kthLargest.add(4));
+        }
+    }
+
+}
diff --git a/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/package-info.java b/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/package-info.java
new file mode 100644
index 00000000..5247f0a3
--- /dev/null
+++ b/lab-09/src/main/java/cn/iocoder/springboot/labs/lab09/leetcode/package-info.java
@@ -0,0 +1,4 @@
+/**
+ * leetcode 题目解答
+ */
+package cn.iocoder.springboot.labs.lab09.leetcode;