Update

Author: sergeyleschev

0001-0500/0002. Add Two Numbers.swift

@@ -1,13 +1,11 @@
-/**
- * Definition for singly-linked list.
- * public class ListNode {
- *     public var val: Int
- *     public var next: ListNode?
- *     public init() { self.val = 0; self.next = nil; }
- *     public init(_ val: Int) { self.val = val; self.next = nil; }
- *     public init(_ val: Int, _ next: ListNode?) { self.val = val; self.next = next; }
- * }
- */
+/// Definition for singly-linked list.
+/// public class ListNode {
+///     public var val: Int
+///     public var next: ListNode?
+///     public init() { self.val = 0; self.next = nil; }
+///     public init(_ val: Int) { self.val = val; self.next = nil; }
+///     public init(_ val: Int, _ next: ListNode?) { self.val = val; self.next = next; }
+/// }
 
 class Solution {
 
@@ -21,15 +19,15 @@ class Solution {
     // Input: l1 = [2,4,3], l2 = [5,6,4]
     // Output: [7,0,8]
     // Explanation: 342 + 465 = 807.
-    
+
     // Example 2:
     // Input: l1 = [0], l2 = [0]
     // Output: [0]
 
     // Example 3:
     // Input: l1 = [9,9,9,9,9,9,9], l2 = [9,9,9,9]
     // Output: [8,9,9,9,0,0,0,1]
-     
+
     // Constraints:
     // The number of nodes in each linked list is in the range [1, 100].
     // 0 <= Node.val <= 9
@@ -45,34 +43,34 @@ class Solution {
     // - Complexity:
     //   - time: O(max(n, m)), where n is the length of the l1 and m is the length of the l2.
     //   - space: O(max(n, m)), where n is the length of the l1 and m is the length of the l2.
-    
+
     func addTwoNumbers(_ l1: ListNode?, _ l2: ListNode?) -> ListNode? {
         var l1 = l1
         var l2 = l2
         let dummyHead = ListNode(-1)
         var tail: ListNode? = dummyHead
         var carry = 0
-        
+
         while l1 != nil || l2 != nil || carry != 0 {
             var value = carry
-            
+
             if let l1Val = l1?.val {
                 value += l1Val
                 l1 = l1?.next
             }
-            
+
             if let l2Val = l2?.val {
                 value += l2Val
                 l2 = l2?.next
             }
-            
+
             let digit = value % 10
             carry = value / 10
             tail?.next = ListNode(digit)
             tail = tail?.next
         }
-        
+
         return dummyHead.next
     }
 
-}
+}

0001-0500/0003. Longest Substring Without Repeating Characters.swift

@@ -9,22 +9,22 @@ class Solution {
     // Input: s = "abcabcbb"
     // Output: 3
     // Explanation: The answer is "abc", with the length of 3.
-    
+
     // Example 2:
     // Input: s = "bbbbb"
     // Output: 1
     // Explanation: The answer is "b", with the length of 1.
-    
+
     // Example 3:
     // Input: s = "pwwkew"
     // Output: 3
     // Explanation: The answer is "wke", with the length of 3.
     // Notice that the answer must be a substring, "pwke" is a subsequence and not a substring.
-    
+
     // Example 4:
     // Input: s = ""
     // Output: 0
-     
+
     // Constraints:
     // 0 <= s.length <= 5 * 10^4
     // s consists of English letters, digits, symbols and spaces.
@@ -37,15 +37,17 @@ class Solution {
         var string = Array(s)
         var chars: [Character] = []
         let length = s.count
-        
+
         for i in 0..<length {
             let char = string[i]
-            if let same_char_index = chars.firstIndex(of: char) { chars = Array(chars[(same_char_index+1)..<chars.count]) }
+            if let same_char_index = chars.firstIndex(of: char) {
+                chars = Array(chars[(same_char_index + 1)..<chars.count])
+            }
             chars.append(char)
             max = chars.count > max ? chars.count : max
         }
-    
+
         return max
     }
 
-}
+}

0001-0500/0004. Median of Two Sorted Arrays.swift

@@ -73,5 +73,5 @@ class Solution {
 
         return res
     }
-    
-}
+
+}

0001-0500/0005. Longest Palindromic Substring.swift

@@ -21,7 +21,7 @@ class Solution {
     // Example 4:
     // Input: s = "ac"
     // Output: "a"
-     
+
     // Constraints:
     // 1 <= s.length <= 1000
     // s consist of only digits and English letters (lower-case and/or upper-case)
@@ -38,8 +38,8 @@ class Solution {
         for i in 0..<count {
             var tmp = 0
             for j in 0..<count {
-                if (i - j < 0 || i + j > count-1) { break }
-                if (string[i  - j] != string[i + j]) { break }
+                if i - j < 0 || i + j > count - 1 { break }
+                if string[i - j] != string[i + j] { break }
                 max1 = max1 > tmp ? max1 : tmp
                 index1 = max1 > tmp ? index1 : i
                 tmp += 1
@@ -49,24 +49,23 @@ class Solution {
         for i in 0..<count {
             var tmp = 0
             for j in 0..<count {
-                if (i - j < 0 || i + j + 1 > count - 1) { break }
-                if (string[i - j] != string[i + j + 1]) { break }
+                if i - j < 0 || i + j + 1 > count - 1 { break }
+                if string[i - j] != string[i + j + 1] { break }
                 tmp += 1
                 max2 = max2 > tmp ? max2 : tmp
                 index2 = max2 > tmp ? index2 : i
             }
         }
 
-        if ((max1 * 2 + 1) >= max2 * 2) {
+        if (max1 * 2 + 1) >= max2 * 2 {
             let start = s.index(s.startIndex, offsetBy: index1 - max1)
             let end = s.index(s.startIndex, offsetBy: index1 + max1 + 1)
             return String(s[start..<end])
-        } 
-        else {
+        } else {
             let start = s.index(s.startIndex, offsetBy: index2 - max2 + 1)
             let end = s.index(s.startIndex, offsetBy: index2 + max2 + 1)
             return String(s[start..<end])
-        }  
+        }
     }
 
-}
+}

0001-0500/0006. ZigZag Conversion.swift

@@ -11,11 +11,11 @@ class Solution {
     // And then read line by line: "PAHNAPLSIIGYIR"
     // Write the code that will take a string and make this conversion given a number of rows:
     // string convert(string s, int numRows);
-     
+
     // Example 1:
     // Input: s = "PAYPALISHIRING", numRows = 3
     // Output: "PAHNAPLSIIGYIR"
-    
+
     // Example 2:
     // Input: s = "PAYPALISHIRING", numRows = 4
     // Output: "PINALSIGYAHRPI"
@@ -28,7 +28,7 @@ class Solution {
     // Example 3:
     // Input: s = "A", numRows = 1
     // Output: "A"
-     
+
     // Constraints:
     // 1 <= s.length <= 1000
     // s consists of English letters (lower-case and upper-case), ',' and '.'.

0001-0500/0007. Reverse Integer.swift

@@ -21,7 +21,7 @@ class Solution {
     // Example 4:
     // Input: x = 0
     // Output: 0
-     
+
     // Constraints:
     // -2^31 <= x <= 2^31 - 1
 
@@ -31,16 +31,16 @@ class Solution {
         var nums: [Int] = []
         let max: Double = pow(2, 31)
         var res: Int = 0
-        
+
         while val > 0 {
             nums.append(val % 10)
             val = val / 10
         }
-        
+
         for num in nums { res = 10 * res + num }
         res = isNegtive ? -res : res
-        if res < -Int(max) || res > Int(max)  - 1 { res = 0 }
+        if res < -Int(max) || res > Int(max) - 1 { res = 0 }
         return res
     }
 
-}
+}

0001-0500/0008. String to Integer (atoi).swift

@@ -12,11 +12,11 @@ class Solution {
     // Convert these digits into an integer (i.e. "123" -> 123, "0032" -> 32). If no digits were read, then the integer is 0. Change the sign as necessary (from step 2).
     // If the integer is out of the 32-bit signed integer range [-2^31, 2^31 - 1], then clamp the integer so that it remains in the range. Specifically, integers less than -2^31 should be clamped to -2^31, and integers greater than 2^31 - 1 should be clamped to 2^31 - 1.
     // Return the integer as the final result.
-    
+
     // Note:
     // Only the space character ' ' is considered a whitespace character.
     // Do not ignore any characters other than the leading whitespace or the rest of the string after the digits.
-     
+
     // Example 1:
     // Input: s = "42"
     // Output: 42
@@ -29,7 +29,7 @@ class Solution {
     //            ^
     // The parsed integer is 42.
     // Since 42 is in the range [-2^31, 2^31 - 1], the final result is 42.
-    
+
     // Example 2:
     // Input: s = "   -42"
     // Output: -42
@@ -42,7 +42,7 @@ class Solution {
     //                ^
     // The parsed integer is -42.
     // Since -42 is in the range [-2^31, 2^31 - 1], the final result is -42.
-    
+
     // Example 3:
     // Input: s = "4193 with words"
     // Output: 4193
@@ -55,7 +55,7 @@ class Solution {
     //              ^
     // The parsed integer is 4193.
     // Since 4193 is in the range [-2^31, 2^31 - 1], the final result is 4193.
-    
+
     // Example 4:
     // Input: s = "words and 987"
     // Output: 0
@@ -68,7 +68,7 @@ class Solution {
     //          ^
     // The parsed integer is 0 because no digits were read.
     // Since 0 is in the range [-2^31, 2^31 - 1], the final result is 0.
-    
+
     // Example 5:
     // Input: s = "-91283472332"
     // Output: -2147483648
@@ -81,7 +81,7 @@ class Solution {
     //                      ^
     // The parsed integer is -91283472332.
     // Since -91283472332 is less than the lower bound of the range [-2^31, 2^31 - 1], the final result is clamped to -2^31 = -2147483648.
-     
+
     // Constraints:
     // 0 <= s.length <= 200
     // s consists of English letters (lower-case and upper-case), digits (0-9), ' ', '+', '-', and '.'.
@@ -101,8 +101,9 @@ class Solution {
                 if isLeading == false { isValid = false }
             case "-", "+":
                 isLeading = false
-                if isSign || nums.count > 0 { isValid = false } 
-                else {
+                if isSign || nums.count > 0 {
+                    isValid = false
+                } else {
                     isSign = true
                     isNegtive = c == "-" ? true : false
                 }
@@ -117,12 +118,18 @@ class Solution {
         for num in nums {
             if num == 0 && isLeadingZero { continue } else { isLeadingZero = false }
             res = num + 10 * res
-            
-            if isNegtive && res > Int(pow(2.0, 31)) { res = Int(pow(2.0, 31)); break }
-            if !isNegtive && res > Int(pow(2.0, 31)) - 1 { res = Int(pow(2.0, 31)) - 1; break }
+
+            if isNegtive && res > Int(pow(2.0, 31)) {
+                res = Int(pow(2.0, 31))
+                break
+            }
+            if !isNegtive && res > Int(pow(2.0, 31)) - 1 {
+                res = Int(pow(2.0, 31)) - 1
+                break
+            }
         }
 
         return isNegtive ? -1 * res : res
     }
 
-}
+}