Find Duplicate in Range 0 and n-1

Code

#include <stdio.h>

int find_duplicate(int arr[], int n) {
    // Your logic here
    int i,j,count=0,arr2[10];
    for( i=0;i<n;i++){
        arr2[i]=arr[i];
    }
    for (i=0;i<n;i++){
        count=0;
        for(j=0;j<n;j++){
            if(arr2[i]==arr[j]) {
                count+=1;
                if (count ==2){
                    return arr2[i];
                    break;
                } 

            }
        }
    }
    
}

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