字符串模式匹配 BF-RK-BM-KMP

    bool patternMatching(string pattern, string value) {
        int m = pattern.size();
        int n = value.size();
       
        for(int i = 0; i <= (n-m); i++){
            int begin = i;
            bool flag = true;
            for(int j = 0; j < m; j++){
                if(pattern[j]!= value[begin+j]){
                    flag = false;
                    break;
                }    
            }
            if(flag) return true;
        }
        retu