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

May LeetCoding Challenge 27

Description

Number of Steps to Reduce a Number to Zero

Given an integer num, return the number of steps to reduce it to zero.

In one step, if the current number is even, you have to divide it by 2, otherwise, you have to subtract 1 from it.

Example 1:

Input: num = 14
Output: 6
Explanation: 
Step 1) 14 is even; divide by 2 and obtain 7. 
Step 2) 7 is odd; subtract 1 and obtain 6.
Step 3) 6 is even; divide by 2 and obtain 3. 
Step 4) 3 is odd; subtract 1 and obtain 2. 
Step 5) 2 is even; divide by 2 and obtain 1. 
Step 6) 1 is odd; subtract 1 and obtain 0.

Example 2:

Input: num = 8
Output: 4
Explanation: 
Step 1) 8 is even; divide by 2 and obtain 4. 
Step 2) 4 is even; divide by 2 and obtain 2. 
Step 3) 2 is even; divide by 2 and obtain 1. 
Step 4) 1 is odd; subtract 1 and obtain 0.

Example 3:

Input: num = 123
Output: 12

Constraints:

• 0 <= num <= 10^6

Solution

class Solution {
public:
  int numberOfSteps (int num) {
    int answer = 0;
    while(num) {
      if(num % 2) num -= 1;
      else num >>= 1;
      ++answer;
    }
    return answer;
  }
};

// Accepted
// 204/204 cases passed (0 ms)
// Your runtime beats 100 % of cpp submissions
// Your memory usage beats 74.11 % of cpp submissions (5.8 MB)