UVA 10167(请帮忙检查一下错误)

#include<stdio.h>
int main()
{
int a,b,i;
int n;
int flag;
int e[100][2];
#ifndef ONLINE_JUDGE
freopen("10167.txt","r",stdin);
#endif
for(;;)
{
scanf("%d",&n);
printf("%d\n",n);
if(n==0)
return 0;
for(i=0;i<2*n;i++){
scanf("%d%d",&e[i][0],&e[i][1]);
}
flag=1;
for(a=-500;a<=500;a++)
{
for(b=-500;b<=500;b++)
{
int countPlus=0;

int countMinus=0;

for(i=0;i<2*n;i++)
{
if((e[i][0]*a+e[i][1]*b)>0)
countPlus++;
if((e[i][0]*a+e[i][1]*b)<0)
countMinus++;
}
if(countPlus==countMinus&&countPlus==n&&countMinus==n){

printf("%d %d\n",a,b);
flag=0;
break;
}

}
if(flag==0)
break;
}
}
return 0;
}

这段代码，我在VC上测试没什么问题，但不知道为什么在UVA提交总是出错误，我真的找不出错误在什么地方，请大家给点指示，谢了。

7 个解决方案

#1

题目是：

Lucy and Lily are twins. Today is their birthday. Mother buys a birthday cake for them.Now we put the cake onto a Descartes coordinate. Its center is at (0,0), and the cake's length of radius is 100.

There are 2N (N is a integer, 1<=N<=50) cherries on the cake. Mother wants to cut the cake into two halves with a knife (of course a beeline). The twins would like to be treated fairly, that means, the shape of the two halves must be the same (that means the beeline must go through the center of the cake) , and each half must have N cherrie(s). Can you help her?

Note: the coordinate of a cherry (x , y) are two integers. You must give the line as form two integers A,B(stands for Ax+By=0), each number in the range [-500,500]. Cherries are not allowed lying on the beeline. For each dataset there is at least one solution.

Input
The input file contains several scenarios. Each of them consists of 2 parts: The first part consists of a line with a number N, the second part consists of 2N lines, each line has two number, meaning (x,y) .There is only one space between two border numbers. The input file is ended with N=0.
Output
For each scenario, print a line containing two numbers A and B. There should be a space between them. If there are many solutions, you can only print one of them.
Sample Input

2
-20 20
-30 20
-10 -50
10 -5
0

Sample Output

0 1

#2

怎么我测试有问题！
接下来就不怎么想看了。。。

#3

你能帮忙先把题目翻译下吗？

#4

for(;;)
{
scanf("%d",&n);
//多了这行 printf("%d\n",n);

没有别的问题。不过以下一行
if(countPlus==countMinus&&countPlus==n&&countMinus==n){
可以简化为
if(countPlus==n&&countMinus==n){

#5

至简化的这个地方是正确的，但我在UVA上总是wrong answer.

#6

你测试的时候出现了什么问题啊？如果是在UVA上提交时，应该先把注释去掉

#7

删除
printf("%d\n",n);
在UVA上可以AC.

#1

#2