Submission #546889

#	Time	Username	Problem	Language	Result	Execution time	Memory
546889		AbdelmagedNour	Collecting Mushrooms (NOI18_collectmushrooms)	C++17	100 / 100	10 ms	5460 KiB

mushrooms

#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
using namespace std;
int n,m,d,k;
vector<vector<int>>pre;
void calc(){
    for(int i=0;i<n;i++){
        for(int j=0;j<m;j++){
            pre[i][j]+=(j?pre[i][j-1]:0)+(i?pre[i-1][j]:0)-(i&&j?pre[i-1][j-1]:0);
        }
    }
}
int sum(int x1,int x2,int y1,int y2){
    int res=pre[x2][y2];
    if(y1)res-=pre[x2][y1-1];
    if(x1)res-=pre[x1-1][y2];
    if(x1&&y1)res+=pre[x1-1][y1-1];
    return res;
}
int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    cin>>n>>m>>d>>k;
    vector<string>grid(n);
    pre.resize(n,vector<int>(m,0));
    for(int i=0;i<n;i++){
        cin>>grid[i];
        for(int j=0;j<m;j++){
            if(grid[i][j]=='S')pre[i][j]++;
        }
    }
    calc();
    int res=0;
    for(int i=0;i<n;i++){
        for(int j=0;j<m;j++){
            if(grid[i][j]=='M'){
                int x1=max(i-d,0),x2=min(i+d,n-1),y1=max(j-d,0),y2=min(j+d,m-1);
                if(sum(x1,x2,y1,y2)>=k)res++;
            }
        }
    }
    cout<<res;
    return 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