solve problems

Author: delight010

number-of-1-bits/delight010.swift

@@ -0,0 +1,14 @@
+class Solution {
+    func hammingWeight(_ n: Int) -> Int {
+        var number = n
+        var answer = 0
+        while number > 0 {
+            if number & 1 == 1 {
+                answer += 1
+            }
+            number = number >> 1
+        }
+        return answer
+    }
+}
+ 

valid-palindrome/delight010.swift

@@ -0,0 +1,29 @@
+class Solution {
+    func isPalindrome(_ s: String) -> Bool {
+        let string = s.replacingOccurrences(of: " ", with: "").lowercased().map { $0 }
+        var leftIndex = string.startIndex
+        var rightIndex = string.endIndex - 1
+        let letterRange: ClosedRange<UInt8> = 97...122
+        let numberRange: ClosedRange<UInt8> = 48...57
+        while leftIndex <= rightIndex {
+            guard let leftCharAscii = string[leftIndex].asciiValue else { break }
+            guard let rightCharAscii = string[rightIndex].asciiValue else { break }
+            if !letterRange.contains(leftCharAscii) && !numberRange.contains(leftCharAscii) {
+                leftIndex += 1
+                continue
+            }
+            if !letterRange.contains(rightCharAscii) && !numberRange.contains(rightCharAscii) {
+                rightIndex -= 1
+                continue
+            }
+            if leftCharAscii == rightCharAscii {
+                leftIndex += 1
+                rightIndex -= 1
+            } else {
+                return false
+            }
+        }
+        return true
+    }
+}
+