[Swift]LeetCode1051.高度檢查器 | Height Checker

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Students are asked to stand in non-decreasing order of heights for an annual photo.

Return the minimum number of students not standing in the right positions.  (This is the number of students that must move in order for all students to be standing in non-decreasing order of height.)

Example 1:

Input: [1,1,4,2,1,3]
Output: 3
Explanation: 
Students with heights 4, 3 and the last 1 are not standing in the right positions.

Note:

1. 1 <= heights.length <= 100
2. 1 <= heights[i] <= 100

---

學校在拍年度記念照時，通常要求學生按照 非遞減 的高度順序排列。

請你返回至少有多少個學生沒有站在正確位置數量。該人數指的是：能讓全部學生以 非遞減 高度排列的必要移動人數。

示例：

輸入：[1,1,4,2,1,3]
輸出：3
解釋：
高度爲 四、3 和最後一個 1 的學生，沒有站在正確的位置。

提示：

1. 1 <= heights.length <= 100
2. 1 <= heights[i] <= 100

---

Runtime: 16 ms

Memory Usage: 21 MB

 1 class Solution {
 2     func heightChecker(_ heights: [Int]) -> Int {
 3         let arr:[Int] = heights.sorted(by:<)
 4         var ret:Int = 0
 5         for i in 0..<arr.count
 6         {
 7             if arr[i] != heights[i]
 8             {
 9                 ret += 1
10             }
11         }
12         return ret
13     }
14 }

---

16ms 

 1 class Solution {        
 2     func heightChecker(_ heights: [Int]) -> Int {
 3         let sortHeights = heights.sorted()
 4         var ans = 0
 5         for i in heights.indices {
 6             if heights[i] != sortHeights[i] {
 7                 ans += 1
 8             }
 9         }
10         return ans
11     }
12 }

---

20ms

 1 class Solution {
 2     func heightChecker(_ heights: [Int]) -> Int {
 3         let sorted = heights.sorted()
 4         var ans = 0
 5         for i in 0..<heights.count where heights[i] != sorted[i] {
 6              ans += 1
 7         }
 8         return ans
 9     }
10 }