Submission #860085

#	Time	Username	Problem	Language	Result	Execution time	Memory
860085		annabeth9680	Collecting Mushrooms (NOI18_collectmushrooms)	C++17	100 / 100	9 ms	3420 KiB

mushrooms

#include <bits/stdc++.h>
using namespace std;
const int MAXN = 5e5+20;
char grid[MAXN];
int pref[MAXN];
int main()
{
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    int R,C,D,K; cin >> R >> C >> D >> K;
    for(int i = 0;i<R;++i){
        for(int j = 0;j<C;++j){
            cin >> grid[i*C+j];
        }
    }
    for(int i = 0;i<R;++i){
        for(int j = 0;j<C;++j){
            if(grid[i*C+j] == 'S'){
                int r1 = max(0,i-D), r2 = min(R-1,i+D), c1 = max(0,j-D), c2 = min(C-1,j+D);
                //cout << r1 << " " << r2 << " " << c1 << " " << c2 << "\n";
                pref[r1*C+c1]++;
                if(r2 != R-1) pref[(r2+1)*C+c1]--;
                if(c2 != C-1) pref[r1*C+c2+1]--;
                if(r2 != R-1 && c2 != C-1) pref[(r2+1)*C+c2+1]++;
            }
        }
    }
    int ans = 0;
    for(int i = 0;i<R;++i){
        for(int j = 0;j<C;++j){
            if(i) pref[i*C+j] += pref[(i-1)*C+j];
            if(j) pref[i*C+j] += pref[i*C+j-1];
            if(i > 0 && j > 0) pref[i*C+j] -= pref[(i-1)*C+j-1];
            if(grid[i*C+j] == 'M' && pref[i*C+j] >= K){
                //cout << pref[i*C+j] << "\n";
                ans++;
            }
        }
    }
    cout << ans << "\n";
    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