/*
 * @lc app=leetcode id=1342 lang=rust
 *
 * [1342] Number of Steps to Reduce a Number to Zero
 *
 * https://leetcode.com/problems/number-of-steps-to-reduce-a-number-to-zero/description/
 *
 * algorithms
 * Easy (87.21%)
 * Total Accepted:    24K
 * Total Submissions: 27.7K
 * Testcase Example:  '14'
 *
 * Given a non-negative integer num, return the number of steps to reduce it to
 * zero. 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
 * 
 * 
 */
impl Solution {
    pub fn number_of_steps (num: i32) -> i32 {
        let mut n = num; 
        let mut res = 0; 
        while n > 0 {
            n = if n % 2 == 0 { n / 2 } else { n - 1 }  ;
            res += 1; 
        }
        res
    }
}
// pub structSolution;