#include <iostream>#include <cstdio>#include <algorithm>#define range(i,a,b) for (int i=a;i<=b;i++)using  std::cin;using  std::cout;using  std::sort;// namespace std has "left" and "right"// if you use them as global variables,there will be an errorconst int maxn = 100000;int pos[maxn+1];int left,right;int n,m;bool check(int val){    int ans(1);    int last(1);    range(c,2,n)        if (pos[c]-pos[last]>=val)        {            last = c;            ans++;        }    return ans >= m;}int main(){    cin>>n>>m;    range(i,1,n)    {        scanf("%d",&pos[i]);    }    sort(pos+1,pos+1+n);    left = 0;    right = pos[n] - pos[1];    range(c,1,60)//i am lazy    {        int mid = (right + left) >> 1;        if (check(mid))        {            left = mid;        }        else        {            right = mid;        }    }    cout<<(left+right)/2;    return 0;}