Find Missing and Duplicate

Problem

An array of length n contains the integers 1 through n with exactly one value duplicated and one value missing.

Scan the array with a set to find the duplicated value, then scan 1 through n to find the value that never appears.

Return [duplicate, missing].

Hint

A set tells you both which value repeats and which of 1..n is absent.

case 1

in: [[1,2,2,4]]

expected: [2,3]

case 2

in: [[1,1]]

expected: [1,2]

case 3

in: [[2,3,3,4]]

expected: [3,1]

case 4

in: [[1,2,3,4,4]]

expected: [4,5]

Starter codePython

def find_missing_duplicate(nums):
    # Your code here
    pass

4 test cases · run your code against them in the editor