#include<iostream>
using namespace std;
int main()
{
long long ans=0,i,b1=0,b2=1;
while(i<4000000){
i = b1+b2;
if(i%2==0){
ans+=i;
}
b1= b2;
b2 = i;
}
cout<<ans<<endl;
return 0;
}
结果:4613732
#include<iostream>
using namespace std;
int main()
{
long long ans=0,i,b1=0,b2=1;
while(i<4000000){
i = b1+b2;
if(i%2==0){
ans+=i;
}
b1= b2;
b2 = i;
}
cout<<ans<<endl;
return 0;
}
结果:4613732