algorithm/Week_02/id_121/LeetCode_687_121.java at master · feixiangcode/algorithm · GitHub

35 lines (34 loc) · 900 Bytes

/**

* Definition for a binary tree node.

* public class TreeNode {

* int val;

* TreeNode left;

* TreeNode right;

* TreeNode(int x) { val = x; }

* }

class Solution {

int result ;

public int longestUnivaluePath(TreeNode root) {

result = 0;

longestLength(root);

return result;

}

public int longestLength(TreeNode node){

if(node == null){

return 0;

}

int left = longestLength(node.left);

int right = longestLength(node.right);

int arrLeft = 0;

int arrRight = 0;

if(node.left != null && node.left.val == node.val){

arrLeft += left + 1;

}

if(node.right != null && node.right.val == node.val){

arrRight += right + 1;

}

result = Math.max(result,arrLeft + arrRight);

return Math.max(arrLeft,arrRight);

}

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