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3394. Minimum Array End

My accepted Python solution to LeetCode problem 3394, Minimum Array End, running in 0ms.

  • Difficulty: Medium
  • Python
  • Runtime 0ms
  • Memory 17.4MB

Read the problem on LeetCode View on GitHub

The problem statement is LeetCode’s and stays on their site. What follows is my accepted solution.

Python

Accepted on LeetCode — runtime 0ms, memory 17.4MB, accepted 2025-12-29.

python
class Solution:
    def minEnd(self, n: int, x: int) -> int:
        # Key insight: We need n elements with AND = x
        # All elements must have all bits of x set
        # The minimum last element is achieved by filling in only the 0-bits of x
        # We essentially "insert" the binary representation of (n-1) into the 0-bit positions of x
        
        # Time: O(64) = O(1), Space: O(1)
        result = x
        n -= 1  # We need to add n-1 more unique numbers after x
        
        bit_pos = 0
        while n > 0:
            # Find the next 0 bit in x
            while (result >> bit_pos) & 1:
                bit_pos += 1
            
            # Set this bit according to the current bit of (n-1)
            if n & 1:
                result |= (1 << bit_pos)
            
            n >>= 1
            bit_pos += 1
        
        return result

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