#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

#define eps 1e-9
#define all(a)   a.begin(),a.end()
#define mp make_pair
#define F first
#define S second
#define pb push_back
#define sz size()
#define rd(inp) scanf("%lld",&inp)
#define rd2(inp1, inp2) scanf("%lld %lld",&inp1, &inp2)
#define rl(inp) scanf("%d",&inp)
#define pf(out) printf("%lld\n", out);

const long long linf = 1e18+5;
const int mod = (int) 1e9 + 7;
const int inf = 1e9;

#define maxn 100100
ll a[maxn], nn, tree[maxn * 8];
vector<ll> d;

void build(ll node, ll start, ll end){
	if(start == end){
		tree[node] = d[start];
	}
	else{
		ll mid = (start + end) / 2;
		build( 2* node + 1 , start, mid);
		build( 2* node + 2, mid + 1, end);
		tree[node] = max(tree[node*2 + 1], tree[node*2+2]);
	}
}

ll query(ll node, ll start, ll end, ll l, ll r){
	if(r < start || end < l){
		return 0;
	}
	if(l <= start && end <=r){
		return tree[node];
	}
	ll mid = (start + end) / 2;
	ll p1 = query(2 * node + 1, start, mid, l, r);
	ll p2 = query(2 * node + 2, mid + 1, end, l, r);
	return max(p1, p2);
}

int main(){
	ll n, i, m = 0, k;
	cin >> n >> k;
	for ( i = 0 ; i < n ; i ++ ){
		cin >> a[i];
	}
	for ( i = 1 ; i < n ; i ++ ){
		d.pb(abs(a[i] - a[i - 1]));
		m = max(m, abs(a[i] - a[i - 1]));
	}
	nn = n - 1;
	build(0, 0, nn - 1);
	ll ans = m;
	for ( i = 0 ; i <= k && i < n ; i ++ ){
		ll rem = k - i;
		if ( rem + i == k ){
			ll rg = n - 1 - rem;
			ans = min(ans, query(0, 0, nn - 1, i, rg - 1));
		}
	}
	cout << ans << endl;
	return 0;	
}