给定周长下的三角形数量 Java Edition
基本思路为，确定最长边的范围，对每一种情况求和，最后加以修正
import java.util.Scanner;
import java.io.FileInputStream;
/**
* Created by IntelliJ IDEA.
* User: Yu Fan
* Date: 2005-4-23
* Time: 14:01:29
* To change this template use File | Settings | File Templates.
*/
public class B {
static Scanner in;
static
{
try
{
System.setIn(new FileInputStream("B.txt"));
in = new Scanner(System.in);
}
catch(Exception e)
{
e.printStackTrace();
}
}
public static void main(String[] arg) {
while(in.hasNext())
{
long q=in.nextLong();
long ans=in.nextLong();
long my=0;
long i;
if(q%3==0)
i=q/3;
else
i=q/3+1;
long p;
if(q%2==0)
p=q/2;
else
p=q/2+1;
my=(3*i+3*p-2*q-1)*(p-i)/4;
if((p-i)%4==0)
{
my+=(p-i)/4;
}
else if((p-i)%4==1)
{
if((3*i-q+1)%2==0)
{
my+=(p-i)/4;
}
else
{
my+=(p-i)/4+1;
}
}
else if((p-i)%4>=2)
{
my+=(p-i)/4+1;
}
/* 以上为下面循坏的级数求和
for(i=i;i<p;i++)
{
long k;
k=3*i-q+1;
if(k%2==1)
k=k/2+1;
else
k=k/2;
my+=k;
}
*/
if(my!=ans)
{
System.out.println("Bad luck!");
}
else
{
System.out.println("Congratulations!");
}
}
}
}