LeetCode 2357: Make Array Zero by Subtracting Equal Amounts ·

Table of Contents

Meta Data
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Difficulty: easy First Attempt: 2022-11-21

Submissions: Runtime Error → Accepted

Approach
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Each operation subtracts the smallest positive x: every value equal to x becomes 0 and the differences among larger values stay the same, so distinct values never merge. Each distinct positive value takes exactly one operation: len(set(nums) - {0}) (Hash Table).

My Attempts
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Attempt 1 wrote len(set(nums)) - {0}, misplacing the parenthesis and subtracting a set from an integer (TypeError). len(set(nums) - {0}) passed.

Solution
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class Solution:
    def minimumOperations(self, nums: List[int]) -> int:
        return len(set(nums) - {0})

Complexity
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Time O(n), space O(n).

Mistakes to Avoid
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Zeros need no operation; remove 0 from the set.
Parenthesize the whole set expression: len(set(nums) - {0}).

Interview Explanation
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Subtracting the smallest positive value zeroes its group while preserving the gaps among the rest, so each distinct positive value takes one operation and the answer is their count. Time O(n).