🔗 https://leetcode.com/problems/word-subsets

题目

• 给两个字符串数组，word1 和 word2
• 若每一个 word2 中的字符串，都是字符串 x 的 subset，则表示该字符串 x 是 universal 的
• 返回 word1 中的 universal 的字符串

思路

• 对 word2 中的每一个字符串，进行 char 的频次统计，取 max
• 对比 word1 中的字符串，是否可以是 word2 的父集合，若是，则加入 answer

代码

word">class Solution {
word">public:word">bool subset(unordered_map<word">char, word">int>& m1, unordered_map<word">char, word">int>& m2) {word">for (word">auto pair : m2) {word">char ch = pair.first;word">int cnt = pair.second;word">if (m2[ch] > m1[ch])word">return false;}word">return true;}vector<string> wordSubsets(vector<string>& words1, vector<string>& words2) {vector<string> ans;unordered_map<word">char, word">int> w2;word">for (word">int i = 0; i < words2.size(); i++) {unordered_map<word">char, word">int> tmp;word">for (word">int j = 0; j < words2[i].size(); j++) {tmp[words2[i][j]]++;}word">for (word">auto pair : tmp) {word">char ch = pair.first;w2[ch] = max(w2[ch], tmp[ch]);}}word">for (word">int i = 0; i < words1.size(); i++) {unordered_map<word">char, word">int> w1;word">for (word">int j = 0; j < words1[i].size(); j++) {w1[words1[i][j]]++;}word">if (subset(w1, w2)) {ans.push_back(words1[i]);}}word">return ans;}
};