LEET-T1178: Number of Valid Words for Each Puzzle

#include <bits/stdc++.h>
using namespace std;

vector<string> words, puzzles;

vector<int> findNumOfValidWords(vector<string> &words, vector<string> &puzzles){
    map<int, int> mp;
    for(string &str : words){
        int btw = 0;
        for(int i = 0; i < str.size(); ++i){
            btw |= (1 << (str[i] - 'a'));
        }
        ++mp[btw];
    }
    vector<int> ans;
    for(string &str : puzzles){
        int sum = 0;
        int btw = 0;
        int req = 1 << (str[0] - 'a');
        for(int i = 1; i < str.size(); ++i){
            btw |= (1 << (str[i] - 'a'));
        }
        for(int b = btw; b != 0; b = (b - 1) & btw){
            if(mp.find(b | req) != mp.end()){
                sum += mp[b | req];
            }
        }
        if(mp.find(req) != mp.end()){
            sum += mp[req];
        }
        ans.push_back(sum);
    }
    return ans;
}

int main(){

    int nWord, nPuzzle;
    scanf("%d%d", &nWord, &nPuzzle);
    for(int i = 1; i <= nWord; ++i){
        string str;
        cin >> str;
        words.push_back(str);
    }
    for(int i = 1; i <= nPuzzle; ++i){
        string str;
        cin >> str;
        puzzles.push_back(str);
    }
    for(int x : findNumOfValidWords(words, puzzles)){
        cout << x << ' ';
    }

    return 0;
}