Tontti

#include <algorithm>
#include <cmath>
#include <iostream>
#include <vector>

typedef long long int ll;

using namespace std;

const int N = 2000;

int n, m, x;
int field[N][N];
ll kertyma[N][N];

ll p(int x1_, int y1_, int x2, int y2) {
    int x1 = x1_-1;
    int y1 = y1_-1;
    int a = 0, b = 0, c = 0;
    if (x1 >= 0) {
        a = kertyma[x1][y2];
    }
    if (y1 >= 0) {
        b = kertyma[x2][y1];
    }
    if (x1 >= 0 && y1 >= 0) {
        c = kertyma[x1][y1];
    } else {
        c = 0;
    }
    return kertyma[x2][y2] + c - b - a;
}

int main() {

    cin >> m >> n >> x;

    for (int j = 0; j < m; ++j) {
        for (int i = 0; i < n; ++i) {
            char c;
            cin >> c;
            field[i][j] = c == '*';
        }
    }

    kertyma[0][0] = field[0][0];

    for (int i = 1; i < n; ++i) {
        kertyma[i][0] = kertyma[i-1][0]+field[i][0];
    }

    for (int j = 1; j < m; ++j) {
        kertyma[0][j] = kertyma[0][j-1]+field[0][j];
    }

    for (int i = 1; i < n; ++i) {
        for (int j = 1; j < m; ++j) {
            kertyma[i][j] = field[i][j] + kertyma[i-1][j] + kertyma[i][j-1] - kertyma[i-1][j-1];
        }
    }

    ll result = 0;
    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < m; ++j) {
            int minSize = (int)sqrt(x);
            int maxSize = min(n-i, m-j);
            for (int s = minSize; s <= maxSize; ++s) {
                ll q = p(i, j, i+s-1, j+s-1);
                if (q == x) {
                    ++result;
                }
                if (q > x) {
                    continue;
                }
            }
        }
    }

    cout << result << endl;

    return 0;
}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 1

Verdict: ACCEPTED

Test 3

Group: 1

Verdict: ACCEPTED

Test 4

Group: 1

Verdict: ACCEPTED

Test 5

Group: 1

Verdict: ACCEPTED

Test 6

Group: 2

Verdict: ACCEPTED

Test 7

Group: 2

Verdict: ACCEPTED

Test 8

Group: 2

Verdict: ACCEPTED

Test 9

Group: 2

Verdict: ACCEPTED

Test 10

Group: 2

Verdict: ACCEPTED

Test 11

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 12

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 13

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 14

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 15

Group: 3

Verdict: TIME LIMIT EXCEEDED