Submission #1279683

#	Time	Username	Problem	Language	Result	Execution time	Memory
1279683		hanguyendanghuy	Bitaro the Brave (JOI19_ho_t1)	C++20	100 / 100	207 ms	151400 KiB

joi2019_ho_t1

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define fi first
#define se second
constexpr ll MAXN=3e3+5,MAXV=3e5,MOD=1e9+7,INF=1e18;
ll n,m,i,j,p,k,ans,dem,st,en,cntI[MAXN][MAXN],cntO[MAXN][MAXN];
string s[MAXN];
int main(){
    ios::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    cin>>n>>m;
    for(i=1;i<=n;i++){
        cin>>s[i];
        ll demO=0;
        for(j=1;j<=m;j++){
            if(s[i][j-1]=='O')
                demO++;
            cntO[i][j]=demO;
        }
    }
    for(j=1;j<=m;j++){
        ll demI=0;
        for(i=1;i<=n;i++){
            if(s[i][j-1]=='I') 
                demI++;
            cntI[j][i]=demI;
        }
    }
    for(i=1;i<=n;i++){
        for(j=1;j<=m;j++){
            if(s[i][j-1]=='J'){
                ans+=(cntO[i][m]-cntO[i][j])*(cntI[j][n]-cntI[j][i]);
            }
        }
    }
    cout<<ans;
}

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