pku3258 River Hopscotch

#include<stdio.h>
#include<algorithm>
using namespace std;
int l,n,m;
int a[50005];
bool ok(int t)
{
int k=0,num=0;
for(int i=1;i<=n+1;i++)
{
if(a[i]-k<t) num++;
else k=a[i];
}
if(num<=m) return true;
else return false;
}
int main()
{
while(scanf("%d%d%d",&l,&n,&m)!=EOF)
{
for(int i=1;i<=n;i++) scanf("%d",&a[i]);
a[n+1]=l;
sort(a+1,a+n+2);
int s=0,e=l;
int ans;
while(s<=e)
{
int mid=(s+e)>>1;
if(ok(mid))
{
ans=mid;
s=mid+1;
}
else e=mid-1;
}
printf("%d/n",ans);
}
return 0;
}