There are a great god help have a look at the code?
The original link to http://poj.org/problem? Id=1328

 
#include 
#include 
using namespace std; 
Int n, d; 
Int a [1000] [2]. 
Double x [1000], [2]. 
Double temp. 
Int main () 
{
Int num=0; 
Cin & gt;> N & gt;> d; 
While (n & amp; & D) 
{
Num++; 
Bool flag=true; 
for (int i=0; I & lt; n; I++) 
Cin & gt;> [I] a [0] & gt;> A, [I] [1]. 

for (int i=0; I & lt; n; I++) 
{
If (abs (a [I] [1]) & gt; Abs (d)) 
{
cout <"Case" & lt; Flag=false; 
break; 
} 
} 
If (flag) 
{
for (int i=0; I & lt; n; I++)//calculation for each island, the radar can be placed the coordinates of the scope of the 
{
Double move=SQRT (double (d * d - a [I] a [I] [1] * [1])); 
[I] x [0]=[I] a [0] - a move; 
[I] x [1]=[I] a [0] + move; 
} 
for (int i=0; I & lt; N - 1; Bubble sort i++)//
{
For (int j=n - 1; J & gt; i; J -) 
{
If (x [j] [0] {
Temp=x [j] [0]; 
X [j] [0]=x [1] [0]; 
X [1] [0]=temp; 
Temp=x [j] [1]; 
X [j] [1]=x [1] [1]; 
X [1] [1]=temp; 
} 
} 
} 
Int LD=1; 
Temp=x [0] [1]. 
For (int I=1; I & lt; n; I++) 
{
If (x [I] [0] <=temp) 
{
If (x [I] [1] Temp=x [I] [1]; 
} 
The else 
{
LD++; 
Temp=x [I] [1]; 
} 
} 
cout <"Case" & lt; } 
Cin & gt;> N & gt;> d; 
} 
return 0; 
}