POJ 3069 Saruman's Army

#include<iostream>
#include<algorithm>
#include<string.h>
using namespace std;
int main()
{
int k, n;
while (cin >> k >> n && (k + n) != -2)
{
int a[1003]; int j = 0;
for (int i = 0; i < n; i++)
{
cin >> a[i];
}
sort(a,a + n);
bool b[1002];
memset(b, false, sizeof(b));
int s = 0;
for (int i = 0; i < n; i++)
{
s++;
for (int j = i+1; j < n; j++)
{
if (a[j] - a[i] > k)
{
i = j - 1; break;
}
if (j == n - 1) i = n - 1;
}
for (int j = i+1; j < n; j++)
{
if (a[j] - a[i] > k)
{
i = j - 1; break;
}
if (j == n - 1) i = n - 1;
}
}
cout << s << endl;
}
return 0;
}