g1801_1900.s1850_minimum_adjacent_swaps_to_reach_the_kth_smallest_number

Class Solution

java.lang.Object

g1801_1900.s1850_minimum_adjacent_swaps_to_reach_the_kth_smallest_number.Solution

public class Solution
extends Object

1850 - Minimum Adjacent Swaps to Reach the Kth Smallest Number.

Medium

You are given a string num, representing a large integer, and an integer k.

We call some integer wonderful if it is a permutation of the digits in num and is greater in value than num. There can be many wonderful integers. However, we only care about the smallest-valued ones.

• For example, when num = "5489355142":
  • The 1^st smallest wonderful integer is "5489355214".
  • The 2^nd smallest wonderful integer is "5489355241".
  • The 3^rd smallest wonderful integer is "5489355412".
  • The 4^th smallest wonderful integer is "5489355421".

Return the minimum number of adjacent digit swaps that needs to be applied to num to reach the kth smallest wonderful integer.

The tests are generated in such a way that kth smallest wonderful integer exists.

Example 1:

Input: num = “5489355142”, k = 4

Output: 2

Explanation: The 4^th smallest wonderful number is “5489355421”. To get this number:

• Swap index 7 with index 8: “5489355142” -> “5489355412”

• Swap index 8 with index 9: “5489355412” -> “5489355421”

Example 2:

Input: num = “11112”, k = 4

Output: 4

Explanation: The 4^th smallest wonderful number is “21111”. To get this number:

• Swap index 3 with index 4: “11112” -> “11121”

• Swap index 2 with index 3: “11121” -> “11211”

• Swap index 1 with index 2: “11211” -> “12111”

• Swap index 0 with index 1: “12111” -> “21111”

Example 3:

Input: num = “00123”, k = 1

Output: 1

Explanation: The 1^st smallest wonderful number is “00132”. To get this number:

• Swap index 3 with index 4: “00123” -> “00132”

Constraints:

• 2 <= num.length <= 1000
• 1 <= k <= 1000
• num only consists of digits.

Constructor Summary

Constructors

Constructor and Description
Solution()

Method Summary

Modifier and Type	Method and Description
int	getMinSwaps(String num, int k)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Solution

public Solution()

Method Detail

getMinSwaps

public int getMinSwaps(String num,
                       int k)