2022-11-18 Daily Challenge

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Posted modified:
In: DailyChallenge

Today I have done leetcode's November LeetCoding Challenge with cpp.

November LeetCoding Challenge 18

Description

Ugly Number

An ugly number is a positive integer whose prime factors are limited to 2, 3, and 5.

Given an integer n, return true if n is an ugly number.

 

Example 1:

Input: n = 6
Output: true
Explanation: 6 = 2 × 3

Example 2:

Input: n = 8
Output: true
Explanation: 8 = 2 × 2 × 2

Example 3:

Input: n = 14
Output: false
Explanation: 14 is not ugly since it includes the prime factor 7.

Example 4:

Input: n = 1
Output: true
Explanation: 1 has no prime factors, therefore all of its prime factors are limited to 2, 3, and 5.

 

Constraints:

  • -231 <= n <= 231 - 1

Solution

auto speedup = [](){
  cin.tie(nullptr);
  cout.tie(nullptr);
  ios::sync_with_stdio(false);
  return 0;
}();
class Solution {
public:
  bool isUgly(int n) {
    if(n < 1) return false;
    while(n % 2 == 0) n /= 2;
    while(n % 3 == 0) n /= 3;
    while(n % 5 == 0) n /= 5;
    return n == 1;
  }
};

// Accepted
// 1013/1013 cases passed (0 ms)
// Your runtime beats 100 % of cpp submissions
// Your memory usage beats 20.16 % of cpp submissions (6 MB)
Algorithm