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.
递归,求左右是否平衡,再判断高度差
/** * Definition for binary tree * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right; * TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */ class Solution { public: bool checkBalance(TreeNode *node, int &dep) { if (node == NULL) { dep = 0; return true; } int leftDep, rightDep; bool leftBalance = checkBalance(node->left, leftDep); bool rightBalance = checkBalance(node->right, rightDep); dep = max(leftDep, rightDep)+1; return leftBalance && rightBalance && (abs(rightDep - leftDep) <= 1); } bool isBalanced(TreeNode *root) { int dep; return checkBalance(root, dep); } };