Submission #779455

#	Time	Username	Problem	Language	Result	Execution time	Memory
779455		borisAngelov	Bitaro the Brave (JOI19_ho_t1)	C++17	100 / 100	266 ms	88524 KiB

joi2019_ho_t1

#include <bits/stdc++.h>

using namespace std;

const int maxn = 3005;

int n, m;

char table[maxn][maxn];

int preffix1[maxn][maxn];
int preffix2[maxn][maxn];

void fastIO()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
}

int main()
{
    fastIO();

    cin >> n >> m;

    for (int i = 1; i <= n; ++i)
    {
        for (int j = 1; j <= m; ++j)
        {
            cin >> table[i][j];
        }
    }

    for (int i = 1; i <= n; ++i)
    {
        for (int j = 1; j <= m; ++j)
        {
            preffix1[i][j] = preffix1[i][j - 1] + (table[i][j] == 'O');
        }
    }

    for (int j = 1; j <= m; ++j)
    {
        for (int i = 1; i <= n; ++i)
        {
            preffix2[i][j] = preffix2[i - 1][j] + (table[i][j] == 'I');
        }
    }

    long long ans = 0;

    for (int i = 1; i <= n; ++i)
    {
        for (int j = 1; j <= m; ++j)
        {
            if (table[i][j] == 'J')
            {
                ans += (preffix1[i][m] - preffix1[i][j]) * (preffix2[n][j] - preffix2[i][j]);
            }
        }
    }

    cout << ans << endl;

    return 0;
}

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