Submission #925582

#	Time	Username	Problem	Language	Result	Execution time	Memory
925582		vjudge1	Collecting Mushrooms (NOI18_collectmushrooms)	C++17	100 / 100	22 ms	26868 KiB

mushrooms

// By ObeliX
#include <bits/stdc++.h>
#pragma GCC target( "sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math,O3")
#include <unordered_map>
#include <cstddef>
#include <cassert>
#include <bitset>
#include <algorithm>
#include <iostream>
#include <iomanip>
#include <cmath>
#include <queue>
#include <map>
#include <set>

using namespace std;

const long long N = 1e6 + 5;
const long long MOD = 1e7 + 7;
const long long inf = 1e18;

long long n , m , d , k;

int main(){
    //freopen( "cinema.in" , "r" , stdin );
    //freopen( "cinema.out" , "w" , stdout );
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    cin >> n >> m >> d >> k;
    char c[n+5][m+5];
    long long pref[n+5][m+5];
    for ( int i = 0 ; i <= n + 1 ; i++ ) {
        for ( int j = 0 ; j <= m + 1 ; j++ ) {
            c[i][j] = '.';
            pref[i][j] = 0;
        }
    }
    long long cnt1 = 0 , cnt2 = 0;
    for ( int i = 1 ; i <= n ; i++ ) {
        for ( int j = 1 ; j <= m ; j++ ) {
            cin >> c[i][j];
            pref[i][j] += pref[i-1][j];
            pref[i][j] += pref[i][j-1];
            pref[i][j] -= pref[i-1][j-1];
            if ( c[i][j] == 'S' ) {
                pref[i][j]++;
            }
        }
    }
    long long ans = 0;
    for ( int i = 1 ; i <= n ; i++ ) {
        for ( int j = 1 ; j <= m ; j++ ) {
            if ( c[i][j] == 'M' ) {
                long long x2 = min( n , i + d ) , y2 = min( m , j + d );
                long long x1 = max( 0ll , i - d - 1 ) , y1 = max( 0ll , j - d - 1 );
                long long x = pref[x2][y2] - ( pref[x2][y1] + pref[x1][y2] ) + pref[x1][y1];
                if ( x >= k ) {
                    ans++;
                }
            }
        }
    }
    cout << ans;
}

Compilation message (stderr)

mushrooms.cpp: In function 'int main()':
mushrooms.cpp:40:15: warning: unused variable 'cnt1' [-Wunused-variable]
   40 |     long long cnt1 = 0 , cnt2 = 0;
      |               ^~~~
mushrooms.cpp:40:26: warning: unused variable 'cnt2' [-Wunused-variable]
   40 |     long long cnt1 = 0 , cnt2 = 0;
      |                          ^~~~

• Subtask 1: 9 / 9
• Subtask 2: 10 / 10
• Subtask 3: 18 / 18
• Subtask 4: 23 / 23
• Subtask 5: 19 / 19
• Subtask 6: 21 / 21