Find Duplicate in Range 0 and n-1

Code

#include <stdio.h>

int find_duplicate(int arr[], int n) {
    // Your logic here
    // sort it first :- less complex  
    for (int i = 0 ; i < n ; i++)
    {
        for (int j = i + 1 ; j < n ; j++)
        {
            if (arr [i] == arr[j])
            {
                return arr [i];
            }

        }
    }
    


    return -1;
}

int main() {
    int n;
    scanf("%d", &n);

    int arr[100];
    for (int i = 0; i < n; i++) scanf("%d", &arr[i]);

    int result = find_duplicate(arr, n);
    printf("%d", result);
    return 0;
}

Solving Approach