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package g2701_2800.s2717_semi_ordered_permutation;

// #Easy #Array #Simulation #2023_09_15_Time_3_ms_(100.00%)_Space_43.3_MB_(98.28%)

/**
 * 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.`
**/
public class Solution {
    public int semiOrderedPermutation(int[] nums) {
        int a = 1;
        int b = nums.length;
        int idxA = 0;
        int idxB = 0;
        for (int i = 0; i < nums.length; i++) {
            if (nums[i] == a) {
                idxA = i;
            }
            if (nums[i] == b) {
                idxB = i;
            }
        }
        b = b - idxB - 1;
        if (idxB < idxA) {
            return idxA + b - 1;
        } else {
            return idxA + b;
        }
    }
}