[Swift]LeetCode205.同构字符串|IsomorphicStrings

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Given two strings s and t, determine if they are isomorphic.

Two strings are isomorphic if the characters in s can be replaced to get t.

All occurrences of a character must be replaced with another character while preserving the order of characters. No two characters may map to the same character but a character may map to itself.

Example 1:

Input: s = "egg", t = "add"
Output: true

Example 2:

Input: s = "foo", t = "bar"
Output: false

Example 3:

Input: s = "paper", t = "title"
Output: true

Note:
You may assume both s and t have the same length.

给定两个字符串 s 和 t，判断它们是否是同构的。

如果 s 中的字符可以被替换得到 t ，那么这两个字符串是同构的。

所有出现的字符都必须用另一个字符替换，同时保留字符的顺序。两个字符不能映射到同一个字符上，但字符可以映射自己本身。

示例 1:

输入: s = "egg", t = "add"
输出: true

示例 2:

输入: s = "foo", t = "bar"
输出: false

示例 3:

输入: s = "paper", t = "title"
输出: true

说明:
你可以假设 s 和 t 具有相同的长度。

28ms

 1 class Solution {
 2   func isIsomorphic(_ s: String, _ t: String) -> Bool {
 3     let s = Array(s)
 4     let t = Array(t)
 5     
 6     var dict: [Character: Character] = [:]
 7     
 8     for i in 0..<s.count {
 9       if let cache = dict[s[i]] {
10         if cache != t[i] {
11           return false
12         }
13       } else if dict.values.contains(t[i]) {
14         return false
15       } else {
16         dict[s[i]] = t[i]
17       }
18     }
19     
20     return true
21   }
22 }

28ms

 1 class Solution {
 2     func isIsomorphic(_ s: String, _ t: String) -> Bool {
 3         guard s.count == t.count else {
 4             return false
 5         }
 6         
 7         var map: [Character: Character] = [:]
 8         var set: Set<Character> = []
 9         var charsS = Array(s)
10         var charsT = Array(t)
11         for index in 0..<s.count {
12             let charS = charsS[index]
13             let charT = charsT[index]
14             if let char = map[charS] {
15                 if char != charT {
16                     return false
17                 }
18             } else {
19                 if set.contains(charT) {
20                     return false
21                 }
22                 
23                 map[charS] = charT
24                 set.insert(charT)
25             }
26         }
27         
28         return true
29     }
30 }

32ms

 1 class Solution {
 2     func isIsomorphic(_ s: String, _ t: String) -> Bool {
 3         let s = Array(s)
 4         let t = Array(t)
 5         if s.count != t.count { return false }
 6         
 7         var isoMap1 = [Character:Character]()
 8         var isoMap2 = [Character:Character]()
 9         
10         var index = 0
11         
12         while index < s.count {
13             
14             let c1 = s[index]
15             let c2 = t[index]
16             
17             if let saved = isoMap1[c1] {
18                 if saved != c2 {
19                     return false
20                 }
21             } else {
22                 isoMap1[c1] = c2
23             }
24             
25             if let saved = isoMap2[c2] {
26                 if saved != c1 {
27                     return false
28                 }
29             } else {
30                 isoMap2[c2] = c1
31             }
32             index += 1
33         }
34         return true
35     }
36 }

36ms

 1 class Solution {
 2     func isIsomorphic(_ s: String, _ t: String) -> Bool {
 3         var m1 = [Int](repeating: 0, count: 256)
 4         var m2 = [Int](repeating: 0, count: 256)
 5         var s = Array(s)
 6         var t = Array(t)
 7     
 8         for i in 0..<s.count {
 9             let sAscii = Int(s[i].unicodeScalars.first?.value ?? 0)
10             let tAscii = Int(t[i].unicodeScalars.first?.value ?? 0)
11             if m1[sAscii] != m2[tAscii] {
12                 return false
13             }
14             m1[sAscii] = i + 1
15             m2[tAscii] = i + 1
16         }
17     
18         return true
19     }
20 }

44ms

 1 class Solution {
 2     func isIsomorphic(_ s: String, _ t: String) -> Bool {
 3         var s0 = Array(s)
 4         var t0 = Array(t)
 5         var dic = [Character : Character]()
 6         
 7         
 8         for i in 0..<s0.count {
 9             let s1 = s0[i]
10             let t1 = t0[i]
11             if let tmp = dic[s1]  {
12                 if tmp == t1 {
13                     continue
14                 }else {
15                     return false
16                 }
17             }else {
18                 if dic.values.contains(t1) {
19                     return false
20                 }
21                 dic[s1] = t1
22             }
23         }
24         
25         return true
26     }
27 }

52ms

 1 class Solution {
 2     func isIsomorphic(_ s: String, _ t: String) -> Bool {
 3         var mapS = [Character:Character]()
 4         var mapT = [Character:Character]()
 5         for idx in 0 ..< s.count {
 6             let cs = s[String.Index.init(encodedOffset: idx)]
 7             let ct = t[String.Index.init(encodedOffset: idx)]
 8             
 9             if let c = mapT[ct] {
10                 if c != cs {
11                     return false
12                 }
13             } else {
14                 mapT[ct] = cs
15             }
16             
17             if let c = mapS[cs] {
18                 if c != ct {
19                     return false
20                 }
21             } else {
22                 mapS[cs] = ct
23             }
24         }
25         return true
26     }
27 }