Submission #3631577

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
#define pb push_back
#define mp make_pair
#define rep(i,n) for(int i=0;i<(n);++i)

int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);
	string s;cin >> s;
	int n=s.size(),cnt=0,ma=0,k=0;
	char cur=s.at(0);
	rep(i,n){
		if(s.at(i)=='2'){
			k++;
		}
		else{
			k--;
		}
		if(s.at(i)==cur) cnt++;
		else{
			ma=max(cnt,ma);
			cnt=1;
			cur=s.at(i);
		}
		if(k<0){
			cout << -1 << endl;
			return 0;
		}
	}
	if(k!=0) cout << -1 << endl;
	else cout << ma << endl;
}

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