leetcode_gym/_problems/missingNumber.md

layout, title

layout	title
page	Missing Number

sort

hashset

gauss equation

{% highlight python %}

def missingNumber(self, nums: List[int]) -> int:

n=len(nums)
expected = (n*(n+1))//2
actual = sum(nums)
return expected-actual

{% endhighlight %}

xor

{% highlight python %}

nums = [3,0,1]

n = len(nums)

xor index with value

xor = 0 for i, num in enumerate(nums): xor ^= i^num

xor with length gives you missing num

missing = xor^n

print(missing)

{% endhighlight %}