Codeforces Round #230 (Div. 2) C. Blocked Points

画个图找规律。

#include<cstdio>#include<cstring>#include<iostream>#include<cmath>using namespace std;int main(){int n;while(cin>>n){if(n==0){cout<<1<<endl;continue;}double len=sqrt(2)/2*n;int l=len;int k=l+1;if((l*l+(l+1)*(l+1))<=n*n)cout<<(k*2-1)*4<<endl;elsecout<<(k*2-2)*4<<endl;}return 0;}