面试题 04.04. 检查平衡性

面试题 04.04. 检查平衡性

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/**
 * 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 isBalanced(TreeNode* root) {
        check(root);
        return ret;
    }
private:
    bool ret = true;
    int check(TreeNode* root)
    {
        if(!root || !ret)
            return 0;
        auto left = check(root->left);
        auto right = check(root->right);
        if(abs(left -right) > 1)
            ret = false;
        return max(left, right) + 1;
    }
};