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
37
#include <bits/stdc++.h>
using namespace std;

const int N = 5 * 1e5 + 3;
int tab[N];

bool bylo[N];

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    // for (int i = 0; i < N; i ++) {tab[i] = 0; bylo[i] = 0;}
    int n, k;
    cin >> n >> k;
    for (int i = 0; i < n; i ++) cin >> tab[i];
    int ans = 0;
    int lz = -1;
    for (int i = 0; i < n; i ++){
        if (bylo[tab[i]]){
            if (lz == -1) lz = i;
            continue;
        }
        bylo[tab[i]] = 1;
        if (lz == -1) continue;
        if (lz < k) ans += (i - lz);
        else break;
        lz ++;
    }
    if (lz < k && lz != -1){
        cout << "-1\n";
        return 0;
    }
    cout << ans << "\n";
    return 0;
}
// #include "testarka.cpp"