Submission #390459

#	Time	Username	Problem	Language	Result	Execution time	Memory
390459		keta_tsimakuridze	JJOOII 2 (JOI20_ho_t2)	C++14	100 / 100	13 ms	5488 KiB

ho_t2

#include<bits/stdc++.h>
#define f first
#define int long long
#define s second
using namespace std;
const int N=2e5+5,mod=1e9+7;
int t,ans,pref[N],n,k,L[N],R[N];
string s;
 main(){
	// t=1;
	cin>>n>>k;
	cin>>s;
	s='#'+s+'#';
	int cnt=0,r=0;
	for(int i=0;i<=n;i++){
		if( s[i]=='J') cnt--;
		while(r+1<=n && cnt<k) {
			r++;
			if(s[r]=='J') cnt++;
		}
		R[i]=r;
		if(cnt < k) R[i]=-1;
		for(int j=0;j<3;j++){
			pref[i]=pref[i-1];
		}
		if(s[i]=='O') pref[i]++;
	} 
	cnt=0; r=n+1;
	for(int i=n+1;i>=1;i--){
		if(s[i]=='I') cnt--;
		while(r-1>=1 && cnt<k) {
			r--;
			if(s[r]=='I') cnt++;
		}
		L[i]=r;
		if(cnt<k) L[i]=-1;
	}
	r=1; ans=n+5;

	for(int i=0;i<=n;i++){
		if(R[i]==-1) break;
		while(r<=n+1 && (L[r]==-1  || pref[L[r]]-pref[R[i]]<k)) r++;
		if(L[r]!=-1 && pref[L[r]]-pref[R[i]]>=k)ans=min(ans,r-i-1-3*k);
	}
	if(ans==n+5) cout<<-1;
	else cout<<ans;
}

Compilation message (stderr)

ho_t2.cpp:9:7: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
    9 |  main(){
      |       ^

• Subtask 1: 1 / 1
• Subtask 2: 12 / 12
• Subtask 3: 87 / 87