Submission #146971

#	Time	Username	Problem	Language	Result	Execution time	Memory
146971		dongwon0427	Collecting Mushrooms (NOI18_collectmushrooms)	C++14	100 / 100	52 ms	35928 KiB

mushrooms

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<int,int> pii;


int n,m,d,k;
vector<int> A[500005], S[500005];
char tmp[500005];
vector<pii> mush;

int cnt(int x1,int y1,int x2,int y2) {
    x2 = min(x2, n);
    y2 = min(y2, m);

    x1--; y1--;
    x1 = max(0, x1);
    y1 = max(0, y1);

    return S[x2][y2] - S[x1][y2] - S[x2][y1] + S[x1][y1];
}
int main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    cin>>n>>m>>d>>k;

    for(int j=1;j<=n;j++) {
        cin>>tmp;
        int len = strlen(tmp);
        A[j].push_back(0);
        for(int i=0;i<len;i++) {
            A[j].push_back(0);
            if(tmp[i] == 'S') A[j].back() = 1;
            if(tmp[i] == 'M') {
                mush.push_back(pii(j,i+1));
            }
        }
    }

    for(int j=0;j<=m;j++) S[0].push_back(0);
    for(int i=1;i<=n;i++) {
        S[i].push_back(0);
        for(int j=1;j<=m;j++) {
            S[i].push_back(0);
            S[i][j] = A[i][j] + S[i-1][j] + S[i][j-1] - S[i-1][j-1];
        }
    }

    for(int i=1;i<=n;i++) {
        for(int j=1;j<=m;j++) {
            //cout<<S[i][j]<<' ';
        }
       // cout<<'\n';
    }
    //cout<<'\n';

    int ans = 0;
    for(pii p : mush) {
        //cout<<p.first<<' '<<p.second<<' '<<cnt(p.first - d, p.second - d, p.first + d, p.second + d)<<'\n';
        ans += (cnt(p.first - d, p.second - d, p.first + d, p.second + d) >= k);
    }
    cout<<ans;
    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