Bit Strings

#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define ull unsigned long long
#define M 1000000007
#define N (1<<18)
#define P complex<long long>
#define X real()
#define Y imag()
 
using namespace std;

ll c[333][2], ans, n, k;

int main() {
	cin.tie(0);
	cout.tie(0);
	ios_base::sync_with_stdio(0);
	cin >> n >> k;
	c[0][0] = 1;
	for(int i=0; i<n; i++) {
		for(int j=0; j<k; j++) {
			c[0][1] += c[j][0];
			c[j+1][1] += c[j][0];
			c[0][0] %= M;
			c[j+1][1] %= M;
		}
		for(int j=0; j<k; j++) {
			c[j][0] = c[j][1];
			c[j][1] = 0;
		}
	}
	for(int j=0; j<k; j++) {
		ans += c[j][0];
		ans %= M;
	}
	cout << ans;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: RUNTIME ERROR

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: RUNTIME ERROR

Test 16

Verdict: RUNTIME ERROR

Test 17

Verdict: RUNTIME ERROR

Test 18

Verdict: RUNTIME ERROR