二分贪心05

Description

Farmer John has built a new long barn, with N (2 <= N <= 100,000) stalls. The stalls are located along a straight line at positions x1,...,xN (0 <= xi <= 1,000,000,000). 

His C (2 <= C <= N) cows don't like this barn layout and become aggressive towards each other once put into a stall. To prevent the cows from hurting each other, FJ want to assign the cows to the stalls, such that the minimum distance between any two of them is as large as possible. What is the largest minimum distance?

Input

* Line 1: Two space-separated integers: N and C 

* Lines 2..N+1: Line i+1 contains an integer stall location, xi

Output

* Line 1: One integer: the largest minimum distance

Sample Input

5 312849

Sample Output

3

Hint

OUTPUT DETAILS: 

FJ can put his 3 cows in the stalls at positions 1, 4 and 8, resulting in a minimum distance of 3. 

Huge input data,scanf is recommended.

这是典型的例题，求最大的最小距离，直接代码

#include <iostream>#include<stdio.h>#include<algorithm>using namespace std;int n,c;int a[100010];int judge(int x)//判断当前的mid是否可以住的下这些牛{    int cnt=1;    int tem=a[1];    for(int i=2;i<=n;++i)    {        if(a[i]-tem>=x)        {            cnt++;            tem=a[i];        }    }    if(cnt>=c)        return 0;    else        return 1;}int main(){    while(cin>>n>>c)    {        for(int i=1;i<=n;++i)            scanf("%d",&a[i]);        sort(a,a+1+n);        int left=0,mid,right=a[n]-a[1];        while(left<=right)        {            mid=(left+right)/2;            if(judge(mid))//住不下                right=mid-1;            else//住下                left=mid+1;        }        printf("%d\n",left-1);    }    return 0;}