1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
#include <bits/stdc++.h>
using namespace std;

using ll = long long;
unordered_map<int, int> idx{};

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    int n{}, k{};
    cin >> n >> k;
    int x{};
    for (int i = 0; i < n; i++) {
        cin >> x;
        if (idx.find(x) == idx.end()) idx[x] = i;
    }
    vector<int> a{};
    for (auto p : idx) a.push_back(p.second);
    if (a.size() < k) {
        cout << "-1\n";
        return 0;
    }
    sort(a.begin(), a.end());
    ll ans{};
    for (int i = 0; i < k; i++) ans += a[i]-i;
    cout << ans << "\n";
}