[LeetCode]110. Balanced Binary Tree

题目描述

、

思路

深搜
初始化为true
当比较左右子树节点差的绝对值大于1的时候赋值为false

代码

#include <iostream>#include <vector>#include <queue>#include <algorithm>using namespace std;struct TreeNode {    int val;    TreeNode* left;    TreeNode* right;    TreeNode(int x) : val(x), left(NULL), right(NULL) {}};class Solution {public:    TreeNode* vectorToTree(vector<int> nums){        if (nums.empty())            return NULL;        TreeNode* root = new TreeNode(nums[0]);        queue<TreeNode*> q;        q.push(root);        for (int i = 1; i < nums.size();) {            int curSize = q.size();            while (curSize--) {                TreeNode* node = q.front();                q.pop();                if (nums[i]) {                    node->left = new TreeNode(nums[i]);                    q.push(node->left);                }                else                    node->left = NULL;                ++i;                if (i == nums.size())                    break;                if (nums[i]) {                    node->right = new TreeNode(nums[i]);                    q.push(node->right);                }                else                    node->right = NULL;                ++i;                if (i == nums.size())                    break;            }        }        return root;    }    bool isBalanced(TreeNode* root) {        maxDepth(root);        return flag;    }    int maxDepth(TreeNode* root) {        if (root == NULL)            return 0;        int leftDepth = maxDepth(root->left),            rightDepth = maxDepth(root->right);        if (abs(leftDepth - rightDepth) > 1)            flag = false;        return max(leftDepth + 1, rightDepth + 1);    }private:    bool flag = true;};int main() {    vector<int> nums = { 1, 0, 1, 1 };    Solution s;    TreeNode* root = s.vectorToTree(nums);    cout << s.isBalanced(root) << endl;    system("pause");    return 0;}