242. 有效字母異位詞 | Valid Anagram

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Given two strings s and t , write a function to determine if t is an anagram of s.

Example 1:

Input: s = "anagram", t = "nagaram"Output: true

Example 2:

Input: s = "rat", t = "car"Output: false

Note:
You may assume the string contains only lowercase alphabets.

Follow up:
What if the inputs contain unicode characters? How would you adapt your solution to such case?

給定兩個字串 s 和 t ，編寫一個函數來判斷 t 是否是 s 的一個字母異位詞。

樣本 1:

輸入: s = "anagram", t = "nagaram"輸出: true

樣本 2:

輸入: s = "rat", t = "car"輸出: false

說明:
你可以假設字串只包含小寫字母。

進階:
如果輸入字串包含 unicode 字元怎麼辦？你能否調整你的解法來應對這種情況？

 

32ms

 1 class Solution { 2     func isAnagram(_ s: String, _ t: String) -> Bool { 3          4       let chars_S = s.unicodeScalars 5       var counter_S = Array(repeating: 0, count: 26) 6       let chars_T = t.unicodeScalars 7       var counter_T = Array(repeating: 0, count: 26) 8  9       for char in chars_S {10         let index = Int(char.value - 97)11         counter_S[index] += 112       }13 14       for char in chars_T {15         let index = Int(char.value - 97)16         counter_T[index] += 117       }18       return counter_T == counter_S19     }20 }

32ms

 1 class Solution { 2     func isAnagram(_ s: String, _ t: String) -> Bool { 3         guard s.count == t.count else { 4             return false 5         } 6         var occurances = [Int](repeating: 0, count: 26) 7         let aValue: UInt8 = 97 8         for char in s.utf8 { 9             occurances[Int(char - aValue)] += 110         }11         for char in t.utf8 {12             occurances[Int(char - aValue)] -= 113         }14         for value in occurances {15             if value != 0 {16                 return false17             }18         }19         return true20     }21 }

48ms

1 class Solution {2     func isAnagram(_ s: String, _ t: String) -> Bool {3         return t.unicodeScalars.reduce(into: [:]) { $0[$1, default: 0] += 1 } == s.unicodeScalars.reduce(into: [:]) { $0[$1, default: 0] += 1 }4     }5 }

64ms

 1 extension Character { 2      3     var ascii: Int { 4         return Int(unicodeScalars.first!.value) 5     } 6      7 } 8  9 class Solution {10     func isAnagram(_ s: String, _ t: String) -> Bool {11         var table = [Int](repeating: 0, count: 128)12 13         for char in s {14             table[char.ascii] += 115         }16 17         for char in t {18             table[char.ascii] -= 119         }20 21         for ascii in 97...122 {22             if table[ascii] != 0 {23                 return false24             }25         }26 27         return true28     }29 }

 

 

242. 有效字母異位詞 | Valid Anagram