Find Duplicate in Range 0 and n-1

Code

#include <stdio.h>

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

    for(int x = 0 ; x < n ; x++)
    {
        int tmp = arr[x];
        for(int y = 0 ; y < n ; y++)
        {
            if((x!=y) && (tmp == arr[y]))
                return arr[y];
        }
    }

    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