minimum-possible-integer-after-at-most-k-adjacent-swaps-on-digits

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1505. Minimum Possible Integer After at Most K Adjacent Swaps On Digits (Hard)

You are given a string num representing the digits of a very large integer and an integer k. You are allowed to swap any two adjacent digits of the integer at most k times.

Return the minimum integer you can obtain also as a string.

 

Example 1:

Input: num = "4321", k = 4
Output: "1342"
Explanation: The steps to obtain the minimum integer from 4321 with 4 adjacent swaps are shown.

Example 2:

Input: num = "100", k = 1
Output: "010"
Explanation: It's ok for the output to have leading zeros, but the input is guaranteed not to have any leading zeros.

Example 3:

Input: num = "36789", k = 1000
Output: "36789"
Explanation: We can keep the number without any swaps.

 

Constraints:

• 1 <= num.length <= 3 * 104
• num consists of only digits and does not contain leading zeros.
• 1 <= k <= 104

Related Topics

[Greedy] [Binary Indexed Tree] [Segment Tree] [String]

Hints

Hint 1

We want to make the smaller digits the most significant digits in the number.

Hint 2

For each index i, check the smallest digit in a window of size k and append it to the answer. Update the indices of all digits in this range accordingly.