邱翎晏 · 发布于 2025-12-26 · 浏览 180 回复 0

long long  N, c=0 ;
cin >> N ;

for (int b = 1; b <= N; b=b+1) {
    if(b%2==0){
    	c=c+b*b;
	}
}
cout << c;
return 0;