leetcode 30 Substring with Concatenation of All Words

题目连接

https://leetcode.com/problems/substring-with-concatenation-of-all-words/  

Substring with Concatenation of All Words

Description

You are given a string, s, and a list of words, words, that are all of the same length. Find all starting indices of substring(s) in s that is a concatenation of each word in wordsexactly once and without any intervening characters.

For example, given:
s: "barfoothefoobarman"
words: ["foo", "bar"]

You should return the indices: [0,9].
(order does not matter).

根据题意直接模拟(写的很挫跑的很慢QAQ)

class Solution {
public:
    vector<int> findSubstring(string s, vector<string>& words) {
        vector<int> res;
        if(s.empty() || words.empty()) return res;
        for(auto &r: words) A[r]++;
        int n = words[0].size(), m = s.size(), k = words.size();
        int len = m - n * k + 1;
        for(int i = 0; i < len; i++) {
            int d = k, j = i;
            B.clear();
            while(d) {
                string temp = s.substr(j, n);
                j += n;
                if(A.find(temp) == A.end()) {
                    break;
                } else {
                    B[temp]++;
                    if(B[temp] > A[temp]) break;
                    d--;
                }
            }
            if(!d) res.push_back(i);
        }
        return res;
    }
private:
    map<string, int> A, B;
};