#include <bits/stdc++.h>
using namespace std;
#define fast ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL)
#define mofile(s) freopen(s,"r",stdin)
#define outfile(s) freopen(s,"w",stdout)
#define ll long long
#define ii pair<ll,ll>
#define iii pair<ll,ii>
#define fi first
#define se second
#define tf bool
#define ST stack
#define Q deque
#define Q queue
#define S string
#define Ma map
#define UM unormideremid_map
#define SE set
#define str(x) to_string(x)
#define all(a) (a).begin(),(a).end()
#define FOR(i,l,r,mid) for(int i=l;i<=r;i+=mid)
#define FOD(i,l,r,mid) for(int i=r;i>=l;i-=mid)
#define xuong cout<<"\n"
#define midebug(x) cout<<(x)<<" "
#define ppcnt(x) __builtin_popcountll(x)
#define parity(x) __builtin_parityll(x)
#define leamid0(x) __builtin_clzll(x)
#define LOG2 __lg(x)
#define tr0(x) __builtin_ctzll(x)
#define fiset(x) __builtin_ffsll(x)
#define MASK(k) (1LL<<(k))
#define BIT(x,k) ((x)>>(k)&1)
#define pb push_back
#define tron(x) setprecision(x)
#define het return 0
#define base_ 1000000000
template<class X, class Y>
bool maximize(X &x, const Y &y){return (x < y) ? x = y, 1 : 0;}
template<class X, class Y>
bool minimize(X &x, const Y &y){return (x > y) ? x = y, 1 : 0;}
const int maxn=1e6+5;
const ll tle=2e8;
const ll INF=1e9+9;
const int base=31;
string bcc="abcmidefghijklmnopqrstuvwxyz";
int midx[]={-1,0,1,0};
int midy[]={0,1,0,-1};
bool sang[10000005];
ll pref[1005][1005],mt[1005][1005];
void sieve(){
for(int i=1;i<=10000000;++i) sang[i]=1;
sang[0]=sang[1]=0;
for(int i=2;i*i<=10000000;++i){
if(sang[i]){
for(int j=i*i;j<=10000000;j+=i) sang[j]=0;
}
}
}
void lis(){
vector<int>t;
vector<int>a;
int n; cin>>n;
for(int i=1;i<=n;++i){
int ai; cin>>ai;
a.pb(ai);
}
for(int x:a){
auto it=lower_bound(all(t),x);
if(it==t.end()) t.pb(x);
else *it=x;
}
}
void pfs2mid(){
int n,m,k; cin>>n>>k; m=n;
for(int i=1;i<=n;++i){
for(int j=1;j<=m;++j) cin>>mt[i][j];
}
for(int i=1;i<=n;++i){
for(int j=1;j<=m;++j) pref[i][j]=mt[i][j]+pref[i-1][j]+pref[i][j-1]-pref[i-1][j-1];
}
}
ll qu2mid(int x1,int y1,int x2,int y2){
return pref[x2][y2]-pref[x1-1][y2]-pref[x2][y1-1]+pref[x1-1][y1-1];
}
void open(){
if(fopen("mideptrai.INP","r")){
mofile("mideptrai.INP");
outfile("mideptrai.OUT");
}
}
#define el '\n'
void run_test()
{
int n, k;
cin >> n >> k;
vector<int> a(n);
for (int i = 0; i < n; ++i)
{
cin >> a[i];
}
sort(all(a));
int lo = 0, hi = 1e15;
auto f = [&](int x) -> int
{
int res = 1, sus = a[0];
for (int i = 1; i < n; i++)
{
if (a[i] - sus >= x) {res++; sus = a[i];}
}
return res;
};
while (lo <= hi)
{
int mid = lo + (hi - lo) / 2;
if (f(mid) >= k) lo = mid + 1;
else hi = mid - 1;
}
cout << hi << el;
}
signed main()
{
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
#ifndef ONLINE_JUDGE
freopen("test.inp", "r", stdin);
freopen("test.out", "w", stdout);
#endif
int test = 1;
// cin >> test;
while (test-- > 0)
{
run_test();
}
}
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