第2問
#include <iostream> #include <time.h> using namespace std; int main() { unsigned long long int l=0; unsigned long long int r=1; unsigned long long int m=0; unsigned long int ans =0; for(long long int i=0;i<=4000000;i++){ if(m>4000000)break; m=l+r; //cout<<m<<endl; if(m%2==0)ans=ans+m; l=r; r=m; } cout<<ans<<endl; }