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 <iostream>
#include <set>
#include <stdint.h>

int main() {
  int N = 0;
  int K = 0;

  std::cin >> N;
  std::cin >> K;

  std::set<int> set;
  int set_size = 0;
  int64_t seconds = 0;

  for (int i = 0; i < N; ++i) {
    int a = 0;
    std::cin >> a;

    if (set.find(a) != set.end()) {
      continue;
    }

    seconds += (i - set_size);
    set.insert(a);
    set_size++;

    if (set_size == K) {
      std::cout << seconds << std::endl;
      return 0;
    }
  }

  std::cout << "-1" << std::endl;
  return 0;
}