[leetcode 17] Letter Combinations of a Phone Number

最新推荐文章于 2025-12-27 20:58:23 发布

原创最新推荐文章于 2025-12-27 20:58:23 发布 · 332 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#leetcode #backtracking

[LeetCode 刷题] 专栏收录该内容

158 篇文章

订阅专栏

本文介绍了一个算法问题：给定一个数字字符串，返回所有可能的字母组合。文章提供了一个C++实现示例，通过深度优先搜索（DFS）遍历所有可能的组合。

Given a digit string, return all possible letter combinations that the number could represent.

A mapping of digit to letters (just like on the telephone buttons) is given below.

Input:Digit string "23"
Output: ["ad", "ae", "af", "bd", "be", "bf", "cd", "ce", "cf"].

Note:

Although the above answer is in lexicographical order, your answer could be in any order you want.

class Solution {
public:
    vector<string> keyboard{" ", "","abc", "def", "ghi", "jkl", "mno", "pqrs", "tuv", "wxyz"};
    vector<string> letterCombinations(string digits) {
        vector<string> res;
        dfs(digits, 0, "", res);
        return res;
    }
    void dfs(string digits, int cur, string path, vector<string> &res) {
        if (cur == digits.size()) {
            res.push_back(path);
            return ;
        }
        for (auto c : keyboard[digits[cur]-'0']) {
            dfs(digits, cur+1, path+c, res);
        }
    }
};