（二分）进击的奶牛

#include <iostream>
#include <cstdio>
#include <algorithm>
using namespace std;
const int N = 100010;
int house[N], n, c;
bool check(int dis){
    int cnt = 1, place = 1; //初始时在第一个位置放一头牛
    for(int i = 2; i <= n; i ++){
        if(house[i] - house[place] >= dis){
            cnt ++;
            place = i;  //假如能在当前位置 i 处满足条件的话，那么更新就要变成这个能放的位置，因
        }               //为如果仅将place++的话有可能出现永远防止不了的情况
    }
    if(cnt < c) return false;
    else return true;
}
int main(){
    scanf("%d%d", &n, &c);
    for(int i = 1; i <= n; i ++) scanf("%d", &house[i]);
    sort(house + 1, house + 1 + n);
    int l = 0, r = house[n] - 1, ans = 0;
    while(l < r){
        int mid = (l + r + 1) >> 1;
        if(check(mid)) r = mid, ans = mid;
        else l = mid + 1;
    }
    cout << ans << endl;

    return 0;
}