codeforces 17A Noldbach problem

#include<cstdio> #include<cmath> #include<algorithm> using namespace std; const int N = 1000; int n, k, ans; bool isPrime (int a) { for (int i = 2; i <= sqrt (a); ++i) if (a % i == 0) return 0; return 1; } int main() { int ai = 1, bi = 0, a[N], b[N]; a[1] = 2; for (int i = 3; i <= N; ++i) if (isPrime (i)) { a[++ai] = i; b[++bi] = a[ai] + a[ai - 1] + 1; } scanf ("%d%d", &n, &k); ans = 0; for (int i = 13; i <= n; ++i) if (isPrime (i) && find (b + 1, b + bi + 1, i) != b + bi + 1) ans++; if (ans >= k) printf ("YES\n"); else printf ("NO\n"); return 0; }

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