leetcode

题目链接
Description
Given an array of strings, group anagrams together.

Example:

Input: [“eat”, “tea”, “tan”, “ate”, “nat”, “bat”],
Output:
[
[“ate”,”eat”,”tea”],
[“nat”,”tan”],
[“bat”]
]

解题思路
题目要求对一组字符串进行分组，将字符串中字符相同只是顺序不同的字符串分到同一组。考虑利用map，首先对每个字符串进行排序，排序后应该被分到同一组的字符串结果相同，利用map做查找和分组。

示例代码

vector<vector<string>> groupAnagrams(vector<string>& strs) {
    map<string, int> strmap;
    int num = 0;
    vector<vector<string>> res;
    for (int i = 0; i < strs.size(); i++)
    {
        string tmp = strs[i];
        sort(strs[i].begin(), strs[i].end());
        if (strmap.count(strs[i]) == 1)
        {
            int index = strmap[strs[i]];
            res[index].push_back(tmp);
        }
        else
        {
            vector<string> tmpvec;
            tmpvec.push_back(tmp);
            res.push_back(tmpvec);
            strmap.insert(pair<string, int>(strs[i],num));
            num++;
        }
    }
    for (int i = 0; i < res.size(); i++)
    {
        for (int j = 0; j < res[i].size(); j++)
            cout << res[i][j] << " ";
        cout << endl;
    }
    return res;
}