Sorting

#include <bits/stdc++.h>
using namespace std;
using int64 = long long;

int main() {
  ios::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
  map<int,int> cnt;
  int n,k; cin >> n >> k;
  for (int i = 0; i < n; ++i) {
    int x; cin >> x;
    ++cnt[x];
  }

  int l = 0;
  vector<int> rem;
  for (auto& x : cnt) {
    l += (x.second/2);
    x.second = x.second&1;
    if (x.second&1) {
      rem.push_back(x.first);
    }
  }
  if (l >= k) {
    cout << 0 << '\n';
    return 0;
  }
  k -= l;
  n = (int)rem.size();
  constexpr int64 INF = 1LL << 60;
  vector<vector<int64>> dp(1+n, vector<int64>(1+k, 0));
  for (int j = 1; j <= k; ++j) {
    for (int i = n; i >= 0; --i) {
      if (i >= n-1) {
        dp[i][j] = INF;
      } else {
        dp[i][j] = min(dp[1+i][j], dp[2+i][j-1]+rem[1+i]-rem[i]);
      }
    }
  }
  cout << dp[0][k] << '\n';
  return 0;
}

Test 1

Group: 1, 2

Verdict: WRONG ANSWER

Test 2

Group: 2

Verdict: WRONG ANSWER

Test 3

Group: 1, 2

Verdict: WRONG ANSWER

Test 4

Group: 1, 2

Verdict: WRONG ANSWER