NYOJ480 Fibonacci Again!

水。

#include <cstdio>#include <cmath>bool f(int n){int t = (int)sqrt(n);for(int i = 2; i <= t; ++i)if(n % i == 0) return 0;return 1;}int main(){int a[30] = {0, 3, 7}, i;for(i = 3; i != 30; ++i)a[i] = a[i - 1] + a[i - 2];while(scanf("%d", &i), i != -1)printf(f(a[i]) == 0 ? "No\n" : "Yes\n");return 0;}