Package g2701_2800.s2717_semi_ordered_permutation

Class Solution

  • public class Solution
extends Object
    2717 - Semi-Ordered Permutation.

    Easy

    You are given a 0-indexed permutation of n integers nums.

    A permutation is called semi-ordered if the first number equals 1 and the last number equals n. You can perform the below operation as many times as you want until you make nums a semi-ordered permutation:

    • Pick two adjacent elements in nums, then swap them.

    Return the minimum number of operations to make nums a semi-ordered permutation.

    A permutation is a sequence of integers from 1 to n of length n containing each number exactly once.

    Example 1:

    Input: nums = [2,1,4,3]

    Output: 2

    Explanation: We can make the permutation semi-ordered using these sequence of operations:

    1 - swap i = 0 and j = 1. The permutation becomes [1,2,4,3].

    2 - swap i = 2 and j = 3. The permutation becomes [1,2,3,4].

    It can be proved that there is no sequence of less than two operations that make nums a semi-ordered permutation.

    Example 2:

    Input: nums = [2,4,1,3]

    Output: 3

    Explanation: We can make the permutation semi-ordered using these sequence of operations:

    1 - swap i = 1 and j = 2. The permutation becomes [2,1,4,3].

    2 - swap i = 0 and j = 1. The permutation becomes [1,2,4,3].

    3 - swap i = 2 and j = 3. The permutation becomes [1,2,3,4].

    It can be proved that there is no sequence of less than three operations that make nums a semi-ordered permutation.

    Example 3:

    Input: nums = [1,3,4,2,5]

    Output: 0

    Explanation: The permutation is already a semi-ordered permutation.

    Constraints:

    • 2 <= nums.length == n <= 50
    • 1 <= nums[i] <= 50
    • nums is a permutation.

    • Constructor Detail

      • Solution

        public Solution()

    • Method Detail

      • semiOrderedPermutation

        public int semiOrderedPermutation​(int[] nums)