WAP in C to find set difference of two arrays?

Question

a = {1, 2, 3, 4, 5, 6}
b={2, 4, 5}
result = {1,3,6}

Answer 1

@ Jai Kumar Garg

DISCLAIMER: I haven't used C in mannnnnnny years (2001-02ish), so I'm use to the more modern languages that handle annoying stuff for you. lol With that being said, here is a simple solution for this. It has room to be improved upon, such as having it check the size of both arrays and create the result array based upon a more dynamic size for it. This could be a really round-about way of doing this, but for the sake of your question, it'll suffice.

https://code.sololearn.com/c2D2oQaI3f3r/#c

#include <stdio.h>
#include <stdbool.h>

int main() {
int arrOne[8] = {1,2,3,4,5,6,9,7}; // Our first array
int arrTwo[3] = {2,4,5}; // Our second array
int result[11]; // Where we'll store the results
int resCounter = 0; // Result counter
bool isSame = false; // Help track unique values

// Outer loop will iterate through our first array
for(int i = 0; i < (sizeof(arrOne)/sizeof(arrOne[0])); ++i) {
// Inner loop will iterate through our sescond array
for(int j = 0; j < (sizeof(arrTwo)/sizeof(arrTwo[0])); ++j) {
// Compare value from arrOne against arrTwo
// If it's the same as any, it's not unique
if(arrOne[i] == arrTwo[j]){
isSame = true;
break;
}
}

// if isSame is false, it's unique. Store it.
if(isSame == false){
// Store value to result array
result[resCounter] = arrOne[i];

// Print unique value
printf("%d ", result[resCounter]);

// Increase result index by 1
++resCounter;
} else {
isSame = false; // Reset our var for next iteration
}
}

return 0;
}

:::: OUTPUT :::::::
1 3 6 9 7

Answer 2

What language you workin with?

Answer 3

You can do it easily in ruby.
a = [1,2,3,4,5,6]
b = [2,4,5]
result = a - b
puts result
Try it yourself in the Ruby's Code Playground.

Answer 4

int is_inset (int *a,int size_of_a,int bi){int i;for (i=0;i<size_of_a;i++){if(a[i]==bi){return 1;}}return -1;}

//elsewhere in the code
int is_in_a,i,k;
int *c;c= (int*)malloc(size_of_c*sizeof(int))
for(i=0,k=0;i <size_of_b;i++){
is_in_a=is_inset (a,size_of_a,b[i]);
if (is_in_a==-1){c [k]=b [i];}}

I didn't test it but thats approximately what I meant
I'm not happy with it I feel like it could be done better I'd be interested to see different (probably better ) ways to do it

Answer 5

Fata1 Err0r in C

Answer 6

Fata1 Err0r good but in worst case scenario the complexity will be O(n*m) can you reduce it to O(n+m). ☺️☺️

where n = length of a
m = length of b

Answer 7

you could make a function that tests if a element of a is in b and if the function return value doesn't indicate a is in b add that element to set c where a-b=c

Answer 8

Rational Agent it would be good if you can show

Answer 9

Rational Agent it's not gonna work