output different elements from two arrays

Question

I am trying to output different elements from two arrays. So if i have an array A: {9, 0, 1} and B is {0, 8, 1}, I need to output an element which included in the first set, but are not included in the second :9 Can not think how I should compare all elements from the first array with the second one.

#include <stdio.h>
#include <stdlib.h>

int main()
{
    int a[10],b[10],c,n,i,j;

    printf("enter a number: ");
    scanf("%d",&n);
    for(i=0;i<n;i++){
    printf("Enter a[%d]: ",i+1);
    scanf("%d",&a[i]);
    }
    printf("\n");
    for(j=0;j<n;j++){
    printf("Enter b[%d]: ",j+1);
    scanf("%d",&b[j]);
    }

    for (i = 0; i < n; i++) {
            printf("%d ", a[i]); }

            printf("\n");

    for (i = 0; i < n; i++) {
            printf("%d ", b[i]); }
            printf("\n");

return 0;
}

I'd like to show my thoughts but i think it's stupid:

 for(i=0;i<n;i++){
        for(j=0;j<n;j++){
            if(a[i]!= b[j]){
                c=a[i];
            }
        }
    printf("%d ",c);
    }

Answer 1

This can be easily solved using Binary search. Follow the simple steps.

Step 1: Sort the second array.

Step 2: For each element of the first array, binary search it in the second array, if its not present , print it, otherwise dont.

The time complexity is O(m log n), where m is length of first array and n is length of second array.