记录详情

#include<iostream>
using namespace std;
int main(){
	int n,s[100001],ans=0;
	char ch;
	cin>>n;
	for(int i=1;i<=n;i++){
		cin>>ch;
		if(ch=='1'){
			s[i]=s[i-1]+1;
		}else{
			s[i]=s[i-1]-1;
		}
	}
	for(int i=1;i<=n;i++){
		for(int j=i+ans;j<=n;j++){
			if(s[j]-s[i-1]==0)ans=max(ans,j-i+1);
		}
	}
	cout<<ans;
}