// Missing Number — EASY

// Category: array

Given an array `nums` containing `n` distinct numbers in the range `[0, n]`, return the only number in the range that is missing from the array.

Hint: The expected sum of [0..n] is `n*(n+1)/2`. Subtract the actual sum to find the missing number.

Example: nums = [3, 0, 1]

Output: 2