[LeetCode]257. Binary Tree Paths

[LeetCode]257. Binary Tree Paths

题目描述

思路

深搜，到叶子节点将当前字符串结果保存到数组中

代码

#include <iostream>
#include <vector>
#include <string>

using namespace std;

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

class Solution {
public:
    void dfs(TreeNode* root, vector<string>& res, string str) {
        if (root == NULL) {
            return;
        }
        if (root->left == NULL && root->right == NULL) {
            res.push_back(str);
            return;
        }
        if (root->left)
            dfs(root->left, res, str + "->" + to_string(root->left->val));
        if (root->right)
            dfs(root->right, res, str + "->" + to_string(root->right->val));
    }

    vector<string> binaryTreePaths(TreeNode* root) {
        vector<string> res;
        if (root == NULL)
            return res;
        string str = to_string(root->val);
        dfs(root, res, str);
        return res;
    }
};

int main() {
    TreeNode* n1 = new TreeNode(1);
    TreeNode* n2 = new TreeNode(2);
    TreeNode* n3 = new TreeNode(3);
    TreeNode* n4 = new TreeNode(5);
    TreeNode* n5 = new TreeNode(6);


    n1->left = n2, n1->right = n3;
    n2->left = n5;
    n2->right = n4;

    Solution s;
    vector<string> res = s.binaryTreePaths(n1);

    for (auto str : res) {
        cout << str << " ";
    }
    cout << endl;

    system("pause");
    return 0;
}