题解 | 分割序列

#include <iostream>
//#include<algorithm>
//#include<cmath>
#include<iostream> 
using namespace std;

typedef long long ll;

ll p = 1000000007;

int main() {
	int n;
	string s;
	cin >> n >> s;
	int p1 = 0, p2 = 0;
	ll ans = 1;
	bool flag = false;
	while (p1 < n) {
		while (p1 < n && s[p1] == '1') {
			p1++;
			flag = true;
		}
//		if (p1 == n) break;
		p2 = p1;
		while (p2 < n && s[p2] == '0') {
			p2++;
			
		}
		if (p2 < n && s[p2] == '1' && flag) {
			ll len = p2 - p1 + 1;
			ans = (ans * len) % p;
		}
		
		p1 = p2;
//		if (p2 == n) break;
	}
	cout << (n > 1 ? ans : 0) << endl;
}