Submission #574054

#	Time	Username	Problem	Language	Result	Execution time	Memory
574054		luka1234	Bitaro the Brave (JOI19_ho_t1)	C++14	100 / 100	843 ms	152904 KiB

joi2019_ho_t1

#include <bits/stdc++.h>
#define ll long long
#define ff first
#define ss second
#define db double
using namespace std;
ll n,m;
ll pref1[3001][3001];
ll pref2[3001][3001];
string s[3001];
int main(){
	cin>>n>>m;
	for(ll i=1;i<=n;i++){
		s[i].push_back('@');
		for(ll j=1;j<=m;j++){
			char c;
			cin>>c;
			s[i].push_back(c);
		}
	}
	for(ll i=1;i<=n;i++){
		for(ll j=1;j<=m;j++){
			pref1[i][j]=pref1[i][j-1];
			if(s[i][j]=='O')
			   pref1[i][j]++;
		}
	}
	for(ll j=1;j<=m;j++){
		for(ll i=1;i<=n;i++){
			pref2[i][j]=pref2[i-1][j];
			if(s[i][j]=='I')
			   pref2[i][j]++;
		}
	}
	ll ans=0;
	for(ll i=1;i<=n;i++){
		for(ll j=1;j<=m;j++){
			if(s[i][j]!='J')
			   continue;
			ll r1=pref1[i][m]-pref1[i][j-1];
			ll r2=pref2[n][j]-pref2[i-1][j];
			ans+=r1*r2;
		}
	}
	cout<<ans;
    return 0;
}

• Subtask 1: 20 / 20
• Subtask 2: 30 / 30
• Subtask 3: 50 / 50