【LeetCode-199】二叉树的右视图

#include <iostream>
#include <vector>
#include <queue>
#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> rightSideView(TreeNode* root)
    {
        queue<TreeNode*> que;
        if(root != nullptr) que.push(root);

        vector<int> result;
        while(!que.empty()){
            int size = que.size();
            for(int i = 0; i < size; i++)
            {
                TreeNode* node = que.front();
                que.pop();
                if(i == size - 1) result.push_back(node->val);

                if(node->left) que.push(node->left);
                if(node->right) que.push(node->right);
            }
        }
        return result;
    }
};