Today I have done leetcode's January LeetCoding Challenge with cpp.

January LeetCoding Challenge 10

Description

Word Subsets

You are given two string arrays words1 and words2.

A string b is a subset of string a if every letter in b occurs in a including multiplicity.

• For example, "wrr" is a subset of "warrior" but is not a subset of "world".

A string a from words1 is universal if for every string b in words2, b is a subset of a.

Return an array of all the universal strings in words1. You may return the answer in any order.

Example 1:

Input: words1 = ["amazon","apple","facebook","google","leetcode"], words2 = ["e","o"]
Output: ["facebook","google","leetcode"]

Example 2:

Input: words1 = ["amazon","apple","facebook","google","leetcode"], words2 = ["l","e"]
Output: ["apple","google","leetcode"]

Constraints:

• 1 <= words1.length, words2.length <= 104
• 1 <= words1[i].length, words2[i].length <= 10
• words1[i] and words2[i] consist only of lowercase English letters.
• All the strings of words1 are unique.

Solution

class Solution {
public:
  vector<string> wordSubsets(vector<string>& A, vector<string>& B) {
    vector<int> count(26);
    for(auto &b : B) {
      vector<int> tmpCount(26);
      for(auto c : b) tmpCount[c - 'a'] += 1;
      for(int i = 0; i < 26; ++i) count[i] = max(count[i], tmpCount[i]);
    }
    
    vector<string> answer;
    for(auto &a : A) {
      vector<int> tmpCount(26);
      for(auto c : a) tmpCount[c - 'a'] += 1;
      bool universal = true;
      for(int i = 0; i < 26; ++i) universal &= tmpCount[i] >= count[i];
      if(universal) answer.push_back(a);
    }
    return answer;
  }
};

// Accepted
// 56/56 cases passed (64 ms)
// Your runtime beats 51.14 % of cpp submissions
// Your memory usage beats 56.16 % of cpp submissions (106.6 MB)