This repository was archived by the owner on Sep 22, 2021. It is now read-only.
This repository was archived by the owner on Sep 22, 2021. It is now read-only.
1346 - Check If N and Its Double Exist #492
Description
Description of the Problem
Given an array arr of integers, check if there exists two integers N and M such that N is the double of M ( i.e. N = 2 * M).
More formally check if there exists two indices i and j such that :
i != j 0 <= i, j < arr.length arr[i] == 2 * arr[j] Example 1:
Input: arr = [10,2,5,3] Output: true Explanation: N = 10 is the double of M = 5,that is, 10 = 2 * 5. Example 2:
Input: arr = [7,1,14,11] Output: true Explanation: N = 14 is the double of M = 7,that is, 14 = 2 * 7. Example 3:
Input: arr = [3,1,7,11] Output: false Explanation: In this case does not exist N and M, such that N = 2 * M. Constraints:
2 <= arr.length <= 500 -10^3 <= arr[i] <= 10^3 Code
class Solution: def checkIfExist(self, arr: List[int]) -> bool: seen = set() for x in arr: if x * 2 in seen or (not x % 2 and x // 2 in seen): return True seen.add(x) return False