【leetcode】Anagrams (middle)

Given an array of strings, return all groups of strings that are anagrams.

Note: All inputs will be in lower-case.

anagrams 的意思是两个词用相同的字母组成  比如 “dog" "god"

思路:

把单词排序 如 dog 按字母排序变为 dgo

用unordered_map<string, int> 记录排序后序列第一次出现时,字符串在输入string向量中的位置

用vector<bool> 记录每个输入字符串是否为anagram, 如果在map中发现已经存在了,就记录当前和初始的字符串都是anagram

class Solution {
public:
    vector<string> anagrams(vector<string> &strs) {
        vector<string> ans;
        vector<bool> isanagrams(strs.size(), false);
        unordered_map<string, int> hash;
        if(strs.size() == 0)
            return ans;

        for(int i = 0; i < strs.size(); i++)
        {
            string cur = strs[i];
            sort(cur.begin(), cur.end());
            if(hash.find(cur) == hash.end()) //没出现过
            {
                hash[cur] = i; //记录第一次出现是strs中的哪一个
            }
            else //出现过
            {
                isanagrams[hash[cur]] = true;
                isanagrams[i] = true;
            }
        }

        for(int j = 0; j < strs.size(); j++)
        {
            if(isanagrams[j] == true)
            {
                ans.push_back(strs[j]);
            }
        }

        return ans;
    }
};
时间: 03-10

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