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LeetCode (1342)Simulation / Bit Counting
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Step 2
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Community-reported · source · updated 2026-10-08. ● asked in the last 6 months.
Given an integer num, return the number of steps to reduce it to zero.
In one step, if the current number is even, you divide it by 2, otherwise you subtract 1 from it.
Input: num = 14
Output: 6
Explanation: 14 → 7 → 6 → 3 → 2 → 1 → 0
Input: num = 8
Output: 4
Explanation: 8 → 4 → 2 → 1 → 0
Input: num = 123
Output: 12
0 ≤ num ≤ 10^6
num /= 2 (in binary: shift right, drops a 0)num -= 1 (in binary: clears the lowest 1)num = 0 → 0 stepsnum = 1 → 1 stepStep 6
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All test cases pass
Step 7
Review it so it sticks
Re-solve from memory after
Reading the solution first feels like progress, but it makes the next similar problem — and the interview version — much harder, because you skipped the part where you figure it out. Give it an honest 20–30 minutes. Stuck? Re-read the pattern, watch the concept video, or try the brute force first.
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