呜呜，全WA，怎么办呀

#include <iostream>
#include <string>
#include <algorithm>
using namespace std;
int n, res;
int days[13] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

int to_int(string date) {
	int res = 0;
	for (int i = 0 ; i < date.size() ; ++i) {
		res = res * 10 + date[i] - '0';
	}
	return res;
}

bool is_prime(string date) {
	int x = to_int(date.substr(6, 2));
	for (int i = 2 ; i <= x / i ; ++ i) {
		if (x % i == 0) return false;
	}
	x = to_int(date.substr(4, 4));
	for (int i = 2 ; i <= x / i ; ++ i) {
		if (x % i == 0) return false;
	}
	x = to_int(date);
	for (int i = 2 ; i <= x / i ; ++ i) {
		if (x % i == 0) return false;
	}
	return true;
}

bool run_year(int x) {
	if ( x % 400 == 0 && x % 100 != 0 || x % 4 == 0 ) return true;
	return false;
}

bool check_valid(int year, int month, int day) {
	if (month == 0 || month > 12) return false;
	if (day == 0) return false;
	if (month != 2) {
		if (day > days[month]) return false;
	} else {
		int leap = year % 400 == 0 && year % 100 != 0 || year % 4 == 0;
		if (day > 28 + leap) return false;
	}
	return true;
}

bool judge(int x)
{
	if(x < 1 || x > 12) return false;
}

bool judge_1(int x)
{
	if(x > 3) return false;
}

void dfs(string date, int idx) {
	//已经是一个完整的数了，判断输出答案
	if(idx > 5 && judge(to_int(date.substr(4 , 2)))) return ;
	if(idx > 6 && judge_1(to_int(date.substr(6 , 1)))) return ;
		
	if (idx >= 8) {
		int year = to_int(date.substr(0, 4)), month = to_int(date.substr(4, 2)), day = to_int(date.substr(6, 2));
		if (check_valid(year, month, day) && is_prime(date)) res++;
		return ;
	} else if (date[idx] == '-') {
		for (int i = 0 ; i <= 9 ; ++i) {
			string p = date;
			p[idx] = i + '0';
			dfs(p, idx + 1);
		}
	} else {
		//当前位数已经确定，直接搜索下一位
		dfs(date, idx + 1);
	}
}

int main() {
	cin >> n;
	while (n--) {
		string date;
		cin >> date;
		res = 0;
		dfs(date, 0);
		cout << res << endl;
	}
	return 0;
}