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input/code.cpp: In function 'int main()':
input/code.cpp:50:26: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   50 |         for (const auto& [k,v] : M) {
      |                          ^

#include <bits/stdc++.h>
using namespace std;
using ll = long long;

using st = int;
#define SE_OP(a, b) a + b

const int N = 1<<18;

st S[N*2];

void init() {
  for (int i = 0; i < N*2; ++i) S[i] = 0;
}

void add(int i, st x) {
  i |= N;
  S[i] = x;
  for (i /= 2; i >= 1; i /= 2) {
    S[i] = SE_OP(S[i*2], S[i*2+1]);
  }
}

st get(int a, int b) {
  a |= N; b |= N;
  st s = 0;
  while (a <= b) {
    if (a % 2 == 1) {
      s = SE_OP(s, S[a]);
      ++a;
    } if (b % 2 == 0) {
      s = SE_OP(s, S[b]);
      --b;
    }
    a /= 2; b /= 2;
  }
  return s;
}

int n, T[N];
map<int,vector<int>> M;

int main() {
  cin >> n;
	for (int i = 0; i < n; ++i) {
		cin >> T[i];
		M[T[i]].push_back(i);
	}
	ll s = 0;
	for (const auto& [k,v] : M) {
		for (int j : v) {
			s += j - get(0,j);
			add(j,1);
		}
	}
	cout << s << '\n';
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED

Test 18

Verdict: ACCEPTED

Test 19

Verdict: ACCEPTED

Test 20

Verdict: ACCEPTED

Test 21

Verdict: ACCEPTED

Test 22

Verdict: ACCEPTED

Test 23

Verdict: ACCEPTED

Test 24

Verdict: ACCEPTED

Test 25

Verdict: ACCEPTED

Test 26

Verdict: ACCEPTED

Test 27

Verdict: ACCEPTED

Test 28

Verdict: ACCEPTED

Test 29

Verdict: ACCEPTED

Test 30

Verdict: ACCEPTED

Test 31

Verdict: ACCEPTED

Test 32

Verdict: ACCEPTED

Test 33

Verdict: ACCEPTED

Test 34

Verdict: ACCEPTED

Test 35

Verdict: ACCEPTED

Test 36

Verdict: ACCEPTED

Test 37

Verdict: ACCEPTED

Test 38

Verdict: ACCEPTED

Test 39

Verdict: ACCEPTED

Test 40

Verdict: ACCEPTED

Test 41

Verdict: ACCEPTED

Test 42

Verdict: ACCEPTED

Test 43

Verdict: ACCEPTED

Test 44

Verdict: ACCEPTED

Test 45

Verdict: ACCEPTED

Test 46

Verdict: ACCEPTED

Test 47

Verdict: ACCEPTED

Test 48

Verdict: ACCEPTED

Test 49

Verdict: ACCEPTED

Test 50

Verdict: ACCEPTED

Test 51

Verdict: ACCEPTED

Test 52

Verdict: ACCEPTED

Test 53

Verdict: ACCEPTED

Test 54

Verdict: ACCEPTED

Test 55

Verdict: ACCEPTED

Test 56

Verdict: ACCEPTED

Test 57

Verdict: ACCEPTED

Test 58

Verdict: ACCEPTED

Test 59

Verdict: ACCEPTED

Test 60

Verdict: ACCEPTED

Test 61

Verdict: ACCEPTED

Test 62

Verdict: ACCEPTED

Test 63

Verdict: ACCEPTED

Test 64

Verdict: ACCEPTED

Test 65

Verdict: ACCEPTED

Test 66

Verdict: ACCEPTED

Test 67

Verdict: ACCEPTED

Test 68

Verdict: ACCEPTED

Test 69

Verdict: ACCEPTED

Test 70

Verdict: ACCEPTED

Test 71

Verdict: ACCEPTED