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热题HOT100_Java/Solution300.java

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+package HOT100;
+
+import java.util.Arrays;
+
+// 最长上升子序列
+public class Solution300 {
+    public int lengthOfLIS(int[] nums) {
+        int n = nums.length;
+        if (n < 2)
+            return n;
+
+        int[] dp = new int[n];
+        Arrays.fill(dp, 1);
+        int res = 1;
+
+        for (int i = 1; i < n; i++) {
+            for (int j = 0; j < i; j++) {
+                if (nums[i] > nums[j]) {
+                    dp[i] = Math.max(dp[i], dp[j] + 1);
+                    res = Math.max(res, dp[i]);
+                }
+            }
+        }
+        return res;
+    }
+}

热题HOT100_Java/Solution406.java

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+package HOT100;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.List;
+
+// 根据身高重建队列
+public class Solution406 {
+    public int[][] reconstructQueue(int[][] people) {
+        if (people.length == 0 || people[0].length == 0)
+            return new int[0][0];
+
+        // 身高降序，K升序
+        Arrays.sort(people, new Comparator<int[]>() {
+            @Override
+            public int compare(int[] o1, int[] o2) {
+                return o1[0] == o2[0] ? o1[1] - o2[1] : o2[0] - o1[0];
+            }
+        });
+
+        // K为索引插入
+        List<int[]> list = new ArrayList<>();
+        for (int[] arr : people) {
+            list.add(arr[1], arr);
+        }
+        return list.toArray(new int[list.size()][]);
+    }
+}

热题HOT100_Java/Solution538.java

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+package HOT100;
+
+
+/*
+class TreeNode {
+    int val;
+    TreeNode left;
+    TreeNode right;
+    TreeNode(int x) { val = x; }
+}
+*/
+
+
+// 把二叉搜索树转换为累加树
+public class Solution538 {
+    int num = 0;
+
+    public TreeNode convertBST(TreeNode root) {
+        if (root != null) {
+            convertBST(root.right);
+            root.val += num;
+            num = root.val;
+            convertBST(root.left);
+        }
+        return root;
+    }
+
+}