[Swift]LeetCode1165. 單行鍵盤 | Single-Row Keyboard

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There is a special keyboard with all keys in a single row.

Given a string keyboard of length 26 indicating the layout of the keyboard (indexed from 0 to 25), initially your finger is at index 0. To type a character, you have to move your finger to the index of the desired character. The time taken to move your finger from index i to index j is |i - j|.

You want to type a string word. Write a function to calculate how much time it takes to type it with one finger. 

Example 1:

Input: keyboard = "abcdefghijklmnopqrstuvwxyz", word = "cba"
Output: 4
Explanation: The index moves from 0 to 2 to write 'c' then to 1 to write 'b' then to 0 again to write 'a'.
Total time = 2 + 1 + 1 = 4. 

Example 2:

Input: keyboard = "pqrstuvwxyzabcdefghijklmno", word = "leetcode"
Output: 73 

Constraints:

• keyboard.length == 26
• keyboard contains each English lowercase letter exactly once in some order.
• 1 <= word.length <= 10^4
• word[i] is an English lowercase letter.

---

咱們定製了一款特殊的力扣鍵盤，全部的鍵都排列在一行上。

咱們能夠按從左到右的順序，用一個長度爲 26 的字符串 keyboard （索引從 0 開始，到 25 結束）來表示該鍵盤的鍵位佈局。

如今須要測試這個鍵盤是否可以有效工做，那麼咱們就須要個機械手來測試這個鍵盤。

最初的時候，機械手位於左邊起第一個鍵（也就是索引爲 0 的鍵）的上方。當機械手移動到某一字符所在的鍵位時，就會在終端上輸出該字符。

機械手從索引 i 移動到索引 j 所須要的時間是 |i - j|。

當前測試須要你使用機械手輸出指定的單詞 word，請你編寫一個函數來計算機械手輸出該單詞所需的時間。 

示例 1：

輸入：keyboard = "abcdefghijklmnopqrstuvwxyz", word = "cba"
輸出：4
解釋：
機械手從 0 號鍵移動到 2 號鍵來輸出 'c'，又移動到 1 號鍵來輸出 'b'，接着移動到 0 號鍵來輸出 'a'。
總用時 = 2 + 1 + 1 = 4. 

示例 2：

輸入：keyboard = "pqrstuvwxyzabcdefghijklmno", word = "leetcode"
輸出：73 

提示：

• keyboard.length == 26
• keyboard 按某種特定順序排列，幷包含每一個小寫英文字母一次。
• 1 <= word.length <= 10^4
• word[i] 是一個小寫英文字母

---

Runtime: 24 ms

Memory Usage: 21.1 MB

 1 class Solution {
 2     func calculateTime(_ keyboard: String, _ word: String) -> Int {
 3         let arr:[Character] = Array(keyboard)
 4         var map:[Character:Int] = [Character:Int]()
 5         for i in 0..<arr.count
 6         {
 7             map[arr[i]] = i
 8         }
 9         var currPos:Int = 0
10         var totalTime:Int = 0
11         for c in word
12         {
13             totalTime += abs(currPos - map[c]!)
14             currPos = map[c]!
15         }
16         return totalTime        
17     }
18 }