Submission #1146147

#	Time	Username	Problem	Language	Result	Execution time	Memory
1146147		AlgorithmWarrior	Bitaro the Brave (JOI19_ho_t1)	C++20	100 / 100	449 ms	79820 KiB

joi2019_ho_t1

#include <bits/stdc++.h>

using namespace std;

int const MAX=3005;
char mat[MAX][MAX];
int drO[MAX][MAX];
int subI[MAX][MAX];
int n,m;

void read(){
    cin>>n>>m;
    int i,j;
    for(i=1;i<=n;++i)
        for(j=1;j<=m;++j)
            cin>>mat[i][j];
}

void precalc(){
    int i,j;
    for(i=1;i<=n;++i)
        for(j=m;j;--j)
            drO[i][j]=drO[i][j+1]+(mat[i][j+1]=='O');
    for(j=1;j<=m;++j)
        for(i=n;i;--i)
            subI[i][j]=subI[i+1][j]+(mat[i+1][j]=='I');
}

long long solve(){
    long long ans=0;
    int i,j;
    for(i=1;i<=n;++i)
        for(j=1;j<=m;++j)
            if(mat[i][j]=='J')
                ans+=drO[i][j]*subI[i][j];
    return ans;
}

void write(long long ans){
    cout<<ans;
}

int main()
{
    read();
    precalc();
    write(solve());
    return 0;
}

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