[leetcode] 320. Generalized Abbreviation 解题报告

题目链接: https://leetcode.com/problems/generalized-abbreviation/

Write a function to generate the generalized abbreviations of a word.

Example:

Given word = "word", return the following list (order does not matter):

["word", "1ord", "w1rd", "wo1d", "wor1", "2rd", "w2d", "wo2", "1o1d", "1or1", "w1r1", "1o2", "2r1", "3d", "w3", "4"]

思路: DFS + 回溯. 每一次如果枚举数字化几位, 需要特殊处理的是不数字话, 这种情况是不加0, 其余情况加数字. 然后维护一个索引代表之前的字符都是处理过的, 现在只需要处理后面的字符. 然后有一个bug让我找了很久, 就是字符串超过11位就会出错, 后来发现我只为数字偏移了一位.

代码如下:

class Solution {
public:
    void DFS(string word, int index)
    {
        if(index >= word.size()) 
        {
            result.push_back(word);
            return;
        }
        DFS(word, index+1);
        for(int i = index; i< word.size(); i++)
        {
            int num = word.size()-i;
            string tem = word.substr(0, index) + to_string(num) + word.substr(index+num);
            DFS(tem, index + to_string(num).size()+1);
        }
    }
    vector<string> generateAbbreviations(string word) {
        DFS(word, 0);
        return result;
    }
private:
    vector<string> result;
};