1013: 防水堤坝

这个最大面积，看了别人找的规律
https://blog.csdn.net/Gong_Yihang/article/details/104986207
我自己不知道为什么lld输出，在手动加上第一位小数，输出可以正常通过
但是如果换成double输出，就会WA50%

include <bits/stdc++.h>

using namespace std;
typedef long long ll;
int main(){
ll k;
while(scanf("%lld",&k)!=EOF){
ll a =k%4;
if(a0){
ll bian= k/4;
ll s= bianbian2;
printf("%lld.0\n",s);
}
else if(a2){
ll short_bian = k/4;
ll long_bian = short_bian+1;
ll s= short_bianlong_bian2;
printf("%lld.0\n",s);
}
else if(a1){
ll bian= k/4;
ll s= bianbian2;
s+=(bian+bian-1)/2;
printf("%lld.5\n",s);
}
else if(a3){
ll short_bian = k/4;
ll long_bian = short_bian+1;
ll s= short_bianlong_bian2;
s+=(long_bian+long_bian-1)/2;
printf("%lld.5\n",s);
}
}
}