Submission #830453

#	Time	Username	Problem	Language	Result	Execution time	Memory
830453		ajay	Collecting Mushrooms (NOI18_collectmushrooms)	C++14	100 / 100	35 ms	38432 KiB

mushrooms

/* Ajay Jadhav */

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <deque>
#include <vector>
#include <cstdlib>
#include <iomanip>
#include <cmath>
#include <queue>
#include <map>
#include <set>
#include <stack>
#include <ctime>
#include <string.h>
#include <climits>
#include <cstring>
using namespace std;

#define ll long long
#define pb push_back
#define pii pair<int, int>
#define vi vector<int>
#define vvi vector<vi>
#define vii vector<pii>
#define mi map<int, int>
#define mii map<pii, int>
#define all(a) (a).begin(), (a).end()
#define x first
#define y second
#define sz(x) (int)x.size()
#define hell 1000000007
#define rep(i, a, b) for (int i = a; i < b; i++)
#define endl '\n'

void solve()
{
    int r, c, d, k;
    cin >> r >> c >> d >> k;
    vvi mat(r + 5, vi(c + 5));
    vvi mushrooms;
    rep(i, 0, r)
    {
        string s;
        cin >> s;
        rep(j, 0, c)
        {
            if (s[j] == 'M')
                mushrooms.pb({i, j});
            else if (s[j] == 'S')
            {
                // 2d range update...
                mat[i][j] = 1;
            }
        }
    }

    rep(i, 0, r)
    {
        rep(j, 0, c)
        {
            if (i > 0)
                mat[i][j] += mat[i - 1][j];
            if (j > 0)
                mat[i][j] += mat[i][j - 1];
            if (i > 0 and j > 0)
                mat[i][j] -= mat[i - 1][j - 1];
        }
    }

    int ans = 0;
    rep(i, 0, sz(mushrooms))
    {
        int xx = mushrooms[i][0];
        int yy = mushrooms[i][1];
        int r1 = max(0, xx - d);
        int r2 = min(r - 1, xx + d);
        int c1 = max(0, yy - d);
        int c2 = min(c - 1, yy + d);
        int sum = mat[r2][c2];
        if (r1 - 1 >= 0)
            sum -= mat[r1 - 1][c2];
        if (c1 - 1 >= 0)
            sum -= mat[r2][c1 - 1];
        if (r1 - 1 >= 0 and c1 - 1 >= 0)
            sum += mat[r1 - 1][c1 - 1];
        if (sum >= k)
        {
            ans++;
        }
    }
    cout << ans << endl;
}

signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int t = 1;
    // cin>>t;
    while (t--)
    {
        solve();
    }
    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