Leetcode 654 MaximumBinaryTree

Author: jiajionline

0654_MaximumBinaryTree/MaximumBinaryTree.java

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+class Solution {
+ public TreeNode constructMaximumBinaryTree(int[] nums) {
+ return build(nums, 0, nums.length-1);
+ }
+
+ private TreeNode build(int[] nums, int l , int r) {
+ if(l > r) return null;
+ int maxIndex = max(nums, l , r);
+ TreeNode root = new TreeNode(nums[maxIndex]);
+ root.left = build(nums, l, maxIndex-1);
+ root.right = build(nums, maxIndex+1, r);
+ return root;
+ }
+
+ private int max(int[] nums, int l , int r) {
+ int max = l;
+ for(int i=l+1;i<=r;i++) {
+ if(nums[max] < nums[i]) max = i;
+ }
+
+ return max;
+ }