题解 100% AC

#include <iostream>
using namespace std;
bool leap(int i){
    if(i%4==0&&i%100!=0||i%400==0)return 1;
    else return 0;
}
int main(){
	int a,b;
    cin>>a>>b;
    int cnt=0;
    for(int i=a;i<=b;i++)if(leap(i))cnt++;
    cout<<cnt<<endl;
	for(int i=a;i<=b;i++)if(leap(i))cout<<i<<" ";
	return 0;
}