二分答案模板题
#include <iostream>
#include <cstdio>
#include <algorithm>
using namespace std;
//Mystery_Sky
//二分查找(模板)
#define M 1000010
#define ll long long
#define Mid (l+r+1)/2
int l, r, mid;
int n, c;
int a[M];
inline bool check(int m)
{
int sum = a[1] + m;
int cnt = 1;
for(int i = 2; i <= n; i++) {
if(a[i] >= sum) cnt++, sum = a[i] + m;
}
return cnt >= c;
}
int main() {
scanf("%d%d", &n, &c);
for(int i = 1; i <= n; i++) scanf("%d", &a[i]);
r = 10000000, l = 0;
sort(a+1, a+n+1);
while(l < r) {//二分答案
mid = Mid;
if(check(mid)) l = mid;
else r = mid - 1;
}
printf("%d
", l);
return 0;
}