#include<bits/stdc++.h>

using namespace std;

#pragma GCC optimize(2)

int a[100001];
int s[100001];

int main(){
	int t=0;
	int n;
	
	cin >> n;
	
	for(int i=1;i<=n;i++){
		cin >> a[i];
		if(a[i]==0){
			a[i] = -1;
		}
		s[i] = a[i]+s[i-1];
	}
	
	for(int i=1;i<=n-1;i++){
		for(int j=i+t;j<=n;j++){
			if(s[j]-s[i] == a[j]-a[i]){
				t = max(t,j-i);
			}
		}
	}
	
	cout << t;
	
	return 0;
}

求助，90pts，#3 WA，#1 TLE