Competitive ProgrammingMedium

Lexicographically smallest array

Detailed guide and Python implementation for the 'Lexicographically smallest array' problem.

Problem Statement

Medium

Write a function lexicographically_smallest(arr, k) that returns the lexicographically smallest array that can be obtained by swapping adjacent elements at most k times. Elements in arr are unique.

Constraints
  • 1 <= len(arr) <= 1000
  • 0 <= k <= 10^5
  • -10^9 <= arr[i] <= 10^9

Examples

Example 1
Input
lexicographically_smallest([7, 6, 9, 2, 1], 3)
Output
[2, 7, 6, 9, 1]
Explanation

To get the smallest possible element 2 to the front, we swap 9 and 2, then 6 and 2, then 7 and 2. This takes exactly 3 swaps, resulting in [2, 7, 6, 9, 1].

Example 2
Input
lexicographically_smallest([2, 1, 3], 1)
Output
[1, 2, 3]
Explanation

Swap 2 and 1 (1 swap) to get [1, 2, 3].

Need a Hint?
Consider using Greedy-specific data structures like sets or heaps.
Edge Cases to Watch
  • Empty input structures
  • Single element inputs
  • Large numerical bounds

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