Given a string,find the length of the longest substring without repeating characters.
Examples:
Given "abcabcbb"
,the answer is "abc"
,which the length is 3.
Given "bbbbb"
,the answer is "b"
,with the length of 1.
Given "pwwkew"
,the answer is "wke"
,with the length of 3. Note that the answer must be a substring, "pwke"
is a subsequence and not a substring.
给定一个字符串,找出不含有重复字符的最长子串的长度。
示例 1:
输入: "abcabcbb" 输出: 3 解释: 无重复字符的最长子串是 长度为 3。 "abc",其
示例 2:
输入: "bbbbb" 输出: 1 解释: 无重复字符的最长子串是 ,其长度为 1。 "b"
示例 3:
输入: "pwwkew" 输出: 3 解释: 无重复字符的最长子串是 ,其长度为 3。 请注意,答案必须是一个子串, 是一个子序列 而不是子串。"wke""pwke"
36ms
1 class Solution { 2 func lengthOfLongestSubstring(_ s: String) -> Int { 3 var m:[Int] = [Int](repeating: -1,count: 256) 4 var res:Int = 0,left:Int = -1 5 for i in 0..<s.count 6 { 7 let num:Int = s[s.index(s.startIndex,offsetBy: i)].toInt() 8 left = max(left,m[num]) 9 m[num] = i 10 res = max(res,i - left) 11 } 12 return res 13 } 14 } 15 //Character扩展方法 16 extension Character 17 { 18 func toInt() -> Int 19 { 20 var num:Int = Int() 21 for scalar in String(self).unicodeScalars 22 { 23 num = Int(scalar.value) 24 } 25 return num 26 } 27 }
20ms
1 class Solution { 2 func lengthOfLongestSubstring(_ s: String) -> Int { 3 var right = 1 4 var left = 0 5 var i = 0 6 var result = 0 7 8 if s.count > 0 { 9 result = right - left 10 let chars = Array(s.utf8) 11 12 //Interate in a incremental window 13 while right < chars.count { 14 i = left 15 while i < right { 16 //Check if a duplicate is found 17 if chars[i] == chars[right] { 18 left = i + 1 19 break 20 } 21 i = i + 1 22 } 23 result = max(result,right-left+1) 24 right = right + 1 25 } 26 } 27 return result 28 } 29 }
28ms
1 class Solution { 2 func lengthOfLongestSubstring(_ s: String) -> Int { 3 if s.characters.count == 0 { 4 return 0 5 } 6 7 let chars = Array(s.utf8) 8 var left = 0 9 var right = 1 10 var result = right - left 11 var i = 0 12 13 while right < chars.count { 14 i = left 15 while i < right { 16 if chars[i] == chars[right] { 17 left = i + 1 18 break 19 } 20 i += 1 21 } 22 result = max(result,right - left + 1) 23 right += 1 24 } 25 26 return result 27 } 28 }
36ms
1 class Solution { 2 func lengthOfLongestSubstring(_ s: String) -> Int { 3 var arr = [Int](repeating: -1,count: 256) 4 var s = Array(s) 5 var currentLength = 0 6 var maxLength = 0 7 for i in 0..<s.count { 8 let cValue = Int(s[i].unicodeScalars.first!.value) 9 let preIndex = arr[cValue] 10 if arr[cValue] == -1 || i - preIndex > currentLength { 11 currentLength += 1 12 } else { 13 maxLength = max(currentLength,maxLength) 14 currentLength = i - preIndex 15 } 16 arr[cValue] = i 17 } 18 19 maxLength = max(currentLength,maxLength) 20 return maxLength 21 } 22 }
44ms
1 class Solution { 2 func lengthOfLongestSubstring(_ s: String) -> Int { 3 4 var last:[Int] = Array.init(repeating: -1,count: 127) 5 var start: Int = 0 // 起始位置 6 var maxLength: Int = 0 // 最大长度 7 8 let chars: [Int8]? = s.cString(using: String.Encoding.utf8) 9 10 for i in 0..<s.count { 11 12 let hash_i: Int = Int(chars![i]) 13 let hash_null: Int = 0 14 15 if (last[hash_i - hash_null] >= start) { 16 maxLength = max(maxLength,i-start) 17 start = last[hash_i - hash_null] + 1 18 } 19 last[hash_i - hash_null] = i 20 } 21 maxLength = max(maxLength,s.count - start) 22 return maxLength 23 } 24 }
52ms
1 class Solution { 2 func lengthOfLongestSubstring(_ s: String) -> Int { 3 let chararr = Array(s) 4 let len = s.count 5 var ans = 0 6 var index = Array.init(repeating: 0,count: 128) 7 var j = 0 8 for i in 0..<len { 9 let char = chararr[i] 10 if let v = char.unicodeScalars.first?.value { 11 j = max(index[Int(v)],j) 12 ans = max(ans,i - j + 1) 13 index[Int(v)] = i + 1 14 } 15 } 16 return ans 17 } 18 }
84ms
1 class Solution { 2 func lengthOfLongestSubstring(_ s: String) -> Int { 3 let cs = s.cString(using: .utf8) 4 guard var chars = cs else { return 0 } 5 guard chars.count > 1 else { 6 return 0 7 } 8 chars.removeLast() 9 var maxCount: Int = 0 10 var i = 0,j = 0 11 var map: [Int8: Int] = [:] 12 while j < chars.count { 13 if map.keys.contains(chars[j]) { 14 i = max(map[chars[j]] ?? 0,i) 15 } 16 maxCount = max(maxCount,j - i + 1) 17 map[chars[j]] = j + 1 18 j += 1 19 } 20 return maxCount 21 } 22 }
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