Find the Missing Number with Bitwise Operators - JavaScript

Using XOR bitwise operator to solve this coding problem

#softwareengineering #javascript #shorts

Music:
Creative Commons / Attribution 4.0 International (CC BY 4.0)

[cnkumar]

n(n+1)/2 give sum of numbers 0 to n
n(n+1)/2 - (sum of all number in array) = missing Number

[JasonKaler]

instead of xor you could use (in the loop)
answer = answer + i - nums[i]
and then just use the positive of answer

[Eumeltier]

I like this version:
const missingNumber = function(nums) {
const max =
let actual = 0;
for(let i = 0; i < nums.length; i++) {
actual = actual + nums[i];
}
return max - actual;
};

[dignum]

I would avoid this solution, based on its lack of readability.

[kkvaruas]

1. create a hashmap off the elements in the array
2. loop thru the hashmap, range should be 0 to n and whichever key is found missing is the answer

[alokpd]

Multiple ways are there
Use case of cyclic sort
Doing sum
Xor

[nimalas]

//Solution in C#:
int missingNumber(int[] nums)
{
var expected = Enumerable.Range(0, nums.Length);

var missing =

return missing.FirstOrDefault();
}

//Usage:
int[] { 3, 0, 2, 1, 4, 5, 6, 8 })); // Returns 7

[calderov]

I'm having trouble following why the for loop goes up to nums.length. Won't that cause i to be equal to n and nums[i] to be an index out of bounds?

If the idea is to have xor compare against n at some point. I think initializing xor = n while keeping i < n is a better approach.

[timhowitz]

Or you could just do (nums.length +1).factorial() - sum(nums). No loop required

[audrianmarak]

Now make the starting number be the smallest integer, let's break it 😂

Although offsetting the xor value could also work

[bhaveshsinghal]

Why can't you just sum the entire array and subtract from n(n+1)/2? Simple and easy

[RedHair]

I thought bitwise XOR literally worked bit by bit. So e.g. 8 ^ 5 == 13 and 3 ^ 3 == 0

[RemoteAccessGG]

1. input_arr.sort()
2. const missing = Array.from({ length: input_arr[input_arr.length - 1] }, (_, index) => index + 1).filter(num => !input_arr.includes(num))[0]

[vighnesh]

Wow. Javascript allows you to xor with undefined (nums[i = nums.length]). Lol. This is so stupid.

[Pluvofor]

Is there a typo in this code? I think that the initial value assigned to the xor variable should be nums.length. Otherwise you'll never have a chance to cancel out the last index.

[arthur.v.babayan]

And what will you do if missed more than one number ?

[JakeKoekemoer]

If there are two numbers missing from the array?

[youssefzayn]

there is a brand new thing called frequency Array you know !!
also keeps the complexity O(n).
you have to loop twice.
but it's much clearer than this fuckin' logic operators shit

[igormizyk]

How do you even come up with this on your own