[数据结构与算法]【LeetCode-515 | 在每个树行中寻找最大值】

1.题目描述

2.题解

#include <iostream>
#include <vector>
#include <queue>
#include <stack>
#include <algorithm>

using namespace std;


struct TreeNode{
    int val;
    TreeNode* left;
    TreeNode* right;
    TreeNode(): val(0), left(nullptr), right(nullptr) {}
    TreeNode(int x): val(x), left(nullptr), right(nullptr) {}
    TreeNode(int x, TreeNode* left, TreeNode* right): val(x), left(left), right(right) {}
};


class Solution {
public:
    vector<int> largestValues(TreeNode* root) {
        vector<int> result;
        queue<TreeNode*> que;

        if(root != nullptr) que.push(root);

        while(!que.empty()) {
            int size = que.size();
            int maxValue = INT_MIN;

            for(int i = 0; i < size; i++) {
                TreeNode* cur = que.front();
                que.pop();
                maxValue = cur->val > maxValue ? cur->val : maxValue;  // 求出每层的最大值并保存在result数组中

                if(cur->left) que.push(cur->left);
                if(cur->right) que.push(cur->right);
            }
            result.push_back(maxValue);
        }
        return result;
    }
};