Find Duplicate in Range 0 and n-1

Code

#include <stdio.h>

int find_duplicate(int arr[], int n) {
    // Your logic here

    for (int i = 0; i < n; i++)
    {
        int duplicate = arr[i];

        for (int j = (i + 1); j < n; j++)
        {
            if (arr[j] == duplicate)
            {
                return duplicate;
            }
        }
        
    }
    
}

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