Submission #156051

#	Time	Username	Problem	Language	Result	Execution time	Memory
156051		user202729	JOIOJI (JOI14_joioji)	C++17	100 / 100	47 ms	6136 KiB

joioji

#include<iostream>
#include<string>
#include<map>

int main(){
	std::ios::sync_with_stdio(0);std::cin.tie(0);
	int n;std::cin>>n;
	std::string s;s.reserve(n);std::cin>>s;

	std::map<std::pair<int,int>,int> minpos;
	minpos.insert({{0,0},-1});
	std::pair<int,int> cur; // {J-I, O-I} count
	int ans=0;
	for(int i=0;i<n;++i){
		switch(s[i]){
			case 'J':++cur.first;break;
			case 'O':++cur.second;break;
			case 'I':--cur.first;--cur.second;break;
			default:__builtin_unreachable();
		}
		auto iter=minpos.find(cur);
		if(iter!=end(minpos))ans=std::max(ans,i-iter->second);
		minpos.insert({cur,i});
	}
	std::cout<<ans<<'\n';
}

• Subtask 1: 5 / 5
• Subtask 2: 15 / 15
• Subtask 3: 80 / 80