poj 2456 Aggressive cows

http://poj.org/problem?id=2456

题意：在n个位置放置c只牛，使得每只牛之间的间距最大，求满足条件的最小间距？

#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>using namespace std;const int NM=100005;int a[NM],n,c;//判断在整个长槽内，间距>=x,是否可以放下c只牛bool getsec(int x){int sec,i,ans;sec=a[0];ans=0;for(i=1;i<n;i++){if(a[i]-sec>=x){ans++;sec=a[i];}if(ans>=c-1) return true;}return false;}int main(){int lf,rg,mid,i;while(~scanf("%d%d",&n,&c)){for(i=0;i<n;i++)scanf("%d",&a[i]);sort(a,a+n);lf=0,rg=a[n-1]-a[0];  //lf=0while(lf<=rg){mid=(lf+rg)>>1;if(getsec(mid)) lf=mid+1;else rg=mid-1;}printf("%d\n",lf-1);  //不可以输出:mid}return 0;}

http://poj.org/problem?id=2456