poj 2456 Aggressive cows 二分

最小的最大

#include <stdio.h>
#include <algorithm>
using namespace std;

int n,c,ar[100005];

void f()
{
    int left,right,mid,num,now,ans,i;
    left=0,right=ar[n-1]-ar[0];
    while (left<=right)
    {
        mid=(left+right)/2;
        for (i=1,now=0,num=1;i<n;i++)
        {
            if(ar[i]-ar[now]>=mid)
            {
                now=i;
                num++;
            }
        }
        if(num>=c)
        {
            ans=mid;
            left=mid+1;
        }
        else right=mid-1;
    }
    printf("%d\n",ans);
}

int main()
{
    int i;
    scanf("%d%d",&n,&c);
    for (i=0;i<n;i++)
    {
        scanf("%d",&ar[i]);
    }
    sort(ar,ar+n);
    f();
    return 0;
}