Andy's Shoes

Here's the problem statement: Andy's Shoes
Accepted in the 3rd try. The last one was with Dileep's help.

#include <iostream>
using namespace std;

void swap(int *arr, int i, int j) {
        int temp = arr[i];
        arr[i] = arr[j];
        arr[j] = temp;
}

int main() {
        int n;
        cin >> n;
        for(int i = 0; i < n; i++) {
                int m;
                cin >> m;
                int arr[2*m], pair[10001];
                for(int j = 0; j < 2*m; j++) {
                        cin >> arr[j];
                        pair[arr[j]] = j;
                }
  
  int s = 0;
                for(int j = 0; j < 2*m; j+=2) {
                        if(arr[j] != arr[j+1]) {
                                if(pair[arr[j+1]] < pair[arr[j]])
                                        pair[arr[j+1]] = pair[arr[j]];
                                swap(arr, pair[arr[j]], j+1);
                                s++;
                        }
                }
                cout << s << endl;
        }
}