POJ - 2456 Aggressive cows

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 3
1
2
8
4
9

Sample Output

3

Hint

把C个牛放在坐标轴上的N个固定点，使得之间最小的距离最大，典型的最大化最小值，此题在检验mid值的时候要注意计算的是牛的距离，所以牛的数量一开始为1

#include <iostream>
#include <algorithm>
using namespace std;

int main()
{
    int n,m,i,l,h,k,t,d;
    int a[100001],b[100001];
    cin>>n>>m;
    for(i=0;i<n;i++){
        cin>>a[i];
    }
    sort(a,a+n);
    h=a[n-1]-a[0];
    l=1;
    for(i=1;i<n;i++){
        b[i]=a[i]-a[i-1];
    }
    while(l<h){
        k=(l+h)/2;
        t=0;
        d=1;
        for(i=1;i<n;i++){
            if(t+b[i]>=k){
                t=0;
                d++;
            }else{
                t+=b[i];
            }
        }
        if(d<m){
            h=k;
        }else{
            l=k+1;
        }
    }
    cout<<l-1<<endl;
    
    return 0;
}