Lähetit

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

using namespace std;

#define ll long long
#define N 1000000007

int n,k;
bool b[100][100];
ll c = 0;

bool ok(int x, int y)
{
	int i = x; int j = y;
	while (i >= 0 && j >= 0) {
		if (b[i--][j--]) return false;
	}
	i = x; j = y;
	while (i < n && j < n) {
		if (b[i++][j++]) return false;
	}
	i = x; j = y;
	while (i >= 0 && j < n) {
		if (b[i--][j++]) return false;
	}
	while (i < n && j >= 0) {
		if (b[i++][j--]) return false;
	}
	return true;
}

void backtrack(int x, int y, int l)
{
	if (l == 0) {
		c = (c+1)%N;
		return;
	}
	for (int i = x; i < n; i++) {
		for (int j = y; j < n; j++) {
			if (ok(i,j)) {
				b[i][j] = true;
				backtrack(i,j,l-1);
				b[i][j] = false;
			}
		}
		x = 0; y = 0;
	}
}

int main()
{
	cin >> n >> k;
	backtrack(0,0,k);
	cout << c << "\n";
}

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: TIME LIMIT EXCEEDED

Test 8

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 9

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 10

Group: 2

Verdict: TIME LIMIT EXCEEDED

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