소수 찾기

#include <string> #include <vector> bool visited[8]; bool check[10000000]; int answer; void brute(int val, int depth, int& max_depth, int& n_size, std::string& numbers) { if (max_depth == depth) { int i = 2; if (val <= 1 || check[val]) return; while (val > i) { if (!(val % i)) return ; i++; } check[val] = 1; answer++; return ; } for (int i = 0 ; i < n_size ; i++) { if (visited[i]) continue; visited[i] = 1; brute(val * 10 + (numbers[i] - '0'), depth + 1, max_depth, n_size, numbers); visited[i] = 0; } } int solution(std::string numbers) { int n_size = numbers.size(); for (int i = 1 ; i <= n_size ; i++) brute(0, 0, i, n_size, numbers); return answer; }