Tontti

#include <bits/stdc++.h>
 
#define i64 long long
#define u64 unsigned long long
#define i32 int
#define u32 unsigned int
 
#define pii pair<int, int>
#define pll pair<long long, long long>
 
#define defmod 1000000007
using namespace std;
 
int s[2020][2020] = {0};
 
int sum(int a, int b, int c, int d){
	int re = s[c][d];
	if(a > 0)
		re-=s[a-1][d];
	if(b > 0)
		re-=s[c][b-1];
	if(a > 0 && b > 0)
		re+=s[a-1][b-1];
	return re;
}
 
int main(){
	cin.sync_with_stdio(0);
	cin.tie(0);
	
	int n, m, x; cin >> n >> m >> x;
	string t[2020];
	for(int i = 0; i < n; i++){
		cin >> t[i];
		int row = 0;
		for(int j = 0; j < m; j++){
			if(t[i][j] == '*')
				row++;
			s[i][j]+=row;
			if(i > 0)
				s[i][j]+=s[i-1][j];
		}
	}
	
	i64 re = 0;
	for(int i = 0; i < n; i++){
		for(int j = 0; j < m; j++){
			int a = 0, b = 0;
			
 
			for(int ad = 1<<20; ad >= 1; ad/=2){
				
				while(i+a+ad < n && j+a+ad < m && sum(i, j, i+a+ad, j+a+ad) < x)
					a+=ad;
			}
			for(int ad = 1<<20; ad >= 1; ad/=2){
				
				while(i+b+ad < n && j+b+ad < m && sum(i, j, i+b+ad, j+b+ad) <= x)
					b+=ad;
			}
			//cout << "paikka " << i << ", " << j << " a-b " << a << "-" << b << endl;
			if(sum(i, j, i+a, j+a) == x)
				re++;
			re+=b-a;
		}
	}
	cout << re << 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: ACCEPTED

Test 12

Group: 3

Verdict: ACCEPTED

Test 13

Group: 3

Verdict: ACCEPTED

Test 14

Group: 3

Verdict: ACCEPTED

Test 15

Group: 3

Verdict: ACCEPTED