Leetcode 448. Find All Numbers Disappeared in an Array

Problem

Given an array nums of n integers where nums[i] is in the range [1, n], return an array of all the integers in the range [1, n] that do not appear in nums.

Algorithm

Use an array to save the number that appeared and serach the missing number in the array.

Code

class Solution:
    def findDisappearedNumbers(self, nums: List[int]) -> List[int]:
        nums_size = len(nums)
        visit = [0] * (nums_size + 1)
        for num in nums:
            visit[num] = 1
        
        ans = []
        for i in range(1, nums_size + 1):
            if not visit[i]:
                ans.append(i)
        
        return ans