LeetCode:Balanced Binary Tree
Given a binary tree, determine if it is height-balanced.
For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees of every node never differ by more than 1.
分析:判断一颗二叉树是否是平衡的,dfs递归求解,递归的过程中顺便求得树的高度 本文地址
1 /** 2 * Definition for binary tree 3 * struct TreeNode { 4 * int val; 5 * TreeNode *left; 6 * TreeNode *right; 7 * TreeNode(int x) : val(x), left(NULL), right(NULL) {} 8 * }; 9 */ 10 class Solution { 11 public: 12 bool isBalanced(TreeNode *root) { 13 // IMPORTANT: Please reset any member data you declared, as 14 // the same Solution instance will be reused for each test case. 15 if(root == NULL)return true; 16 if(height(root) == -1)return false; 17 else return true; 18 } 19 //若root是平衡树,那么返回树的高度,否则返回-1 20 int height(TreeNode *root) 21 { 22 if(root->left == NULL && root->right == NULL)return 1; 23 int leftHeight = 0, rightHeight = 0; 24 if(root->left) 25 leftHeight = height(root->left); 26 if(leftHeight == -1)return -1; 27 if(root->right) 28 rightHeight = height(root->right); 29 if(rightHeight == -1)return -1; 30 if(abs(leftHeight-rightHeight) > 1)return -1; 31 return 1+max(leftHeight, rightHeight); 32 } 33 };
【版权声明】转载请注明出处:http://www.cnblogs.com/TenosDoIt/p/3440069.html