13144.cpp

// Authored by : heheHwang
// Co-authored by : BaaaaaaaaaaarkingDog
// http://boj.kr/20b3510ea5384c78a6e1c34aae40b267
#include <bits/stdc++.h>
using namespace std;

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

  int n;
  cin >> n;
  vector<int> arr(n);
  vector<bool> chk(100'002);
  for (int i = 0; i < n; i++) cin >> arr[i];

  long long ans = 0;
  chk[arr[0]] = 1;
  int en = 0;
  for(int st = 0; st < n; st++){
    // en에는 arr[st] to arr[en]에 같은 수가 등장하지 않는 가장 큰 값이 저장됨
    while (en < n-1 && !chk[arr[en+1]]){
      en++;
      chk[arr[en]] = 1;
    }
    ans += (en-st+1);
    chk[arr[st]] = 0;
  }
  cout << ans;
}