#include<bits/stdc++.h> using namespace std; #define int long long int n,p,r; vector<int>a; int dp[2002][2002]; bool oke(int jrk){ for(int q=1;q<=n;q++){ int bsr=upper_bound(a.begin()+1,a.end(),a[q]-2*jrk)-a.begin()-1; int kcl=upper_bound(a.begin()+1,a.end(),a[q]-jrk)-a.begin()-1; for(int w=0;w<=r;w++){ dp[q][w]=1e18; if(w>=1){ dp[q][w]=min(dp[q][w-1],dp[bsr][w-1]); } dp[q][w]=min(dp[q][w],dp[kcl][w]+1); } } //if(jrk==3)cout<<dp[n][r]<<"K"<<endl; return dp[n][r]<=p; } signed main(){ cin>>n>>p>>r; for(int q=1;q<=n;q++){ int x; cin>>x; a.push_back(x); } a.push_back(0); sort(a.begin(),a.end()); int l=1,r=1e9; int ans=-1; while(l<=r){ int mid=(l+r)/2; if(oke(mid)){ ans=mid; r=mid-1; } else{ l=mid+1; } } cout<<ans<<endl; }