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
29
30
31
32
33
34
35
36
#include <bits/stdc++.h>
using namespace std;

const int MAX_N = 5e5;

int n, k;
int arr[MAX_N + 5];

set<int> found;

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

    cin >> n >> k;
    for (int i = 0; i < n; ++i)
        cin >> arr[i];

    long long result = 0;

    for (int i = 0; i < n && found.size() < k; ++i)
        if (found.count(arr[i]) == 0)
        {
            result += i - found.size();
            found.insert(arr[i]);
        }

    if (found.size() < k)
        cout << "-1\n";
    else
        cout << result << "\n";

    return 0;
}