Leetcode之Cousins in Binary Tree

题目：

In a binary tree, the root node is at depth 0, and children of each depth k node are at depth k+1.

Two nodes of a binary tree are cousins if they have the same depth, but have different parents.

We are given the root of a binary tree with unique values, and the values x and y of two different nodes in the tree.

Return true if and only if the nodes corresponding to the values x and y are cousins.

Example 1:

Input: root = [1,2,3,4], x = 4, y = 3
Output: false

Example 2:

Input: root = [1,2,3,null,4,null,5], x = 5, y = 4
Output: true

Example 3:

Input: root = [1,2,3,null,4], x = 2, y = 3
Output: false

Note:

1. The number of nodes in the tree will be between 2 and 100.
2. Each node has a unique integer value from 1 to 100.

代码：

/*** Definition for a binary tree node.* struct TreeNode {*     int val;*     TreeNode *left;*     TreeNode *right;*     TreeNode(int x) : val(x), left(NULL), right(NULL) {}* };*/
class Solution {
public:bool isCousins(TreeNode* root, int x, int y) {if (!root)return false;queue<TreeNode*> q;q.push(root);while (!q.empty()){int size = q.size(),record=2;for (int i = 0; i < size; i++) {TreeNode* t = q.front(); q.pop();int count = 0;if (t->left) {if (t->left->val == x || t->left->val == y) count++;q.push(t->left);}if (t->right) {if (t->right->val == x || t->right->val == y)count++;q.push(t->right);}if (count == 2)return false;record -= count;}if (record == 0)return true;}return false;}
};