Binary Number with Alternating Bits.

Author: recherst

Easy/326.Power of Three.playground/xcuserdata/recherst.xcuserdatad/xcschemes/xcschememanagement.plist

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>SchemeUserState</key>
+	<dict>
+		<key>326.Power of Three (Playground).xcscheme</key>
+		<dict>
+			<key>isShown</key>
+			<false/>
+			<key>orderHint</key>
+			<integer>0</integer>
+		</dict>
+	</dict>
+</dict>
+</plist>

Easy/693.Binary Number with Alternating Bits.playground/Contents.swift

@@ -0,0 +1,68 @@
+/**
+ Given a positive integer, check whether it has alternating bits: namely, if two adjacent bits will always have different values.
+
+  
+
+ Example 1:
+ Input: n = 5
+ Output: true
+ Explanation: The binary representation of 5 is: 101
+ 
+ Example 2:
+ Input: n = 7
+ Output: false
+ Explanation: The binary representation of 7 is: 111.
+ 
+ Example 3:
+ Input: n = 11
+ Output: false
+ Explanation: The binary representation of 11 is: 1011.
+  
+
+ Constraints:
+ - 1 <= n <= 231 - 1
+ */
+class Solution {
+    func hasAlternatingBits(_ n: Int) -> Bool {
+        var x = 0
+        while pow(2, power: x) <= n {
+            x += 1
+        }
+        var arr = Array(repeating: 0, count: x)
+        
+        var i = n
+        while i != 0 {
+            var x = 0
+            while pow(2, power: x) <= i {
+                x += 1
+            }
+            arr[x - 1] = 1
+            i -= pow(2, power: x - 1)
+        }
+        
+        for (i, c) in arr.enumerated() {
+            if i > 0 {
+                if c == 0 && arr[i - 1] == 0 {
+                    return false
+                } else if c == 1 && arr[i - 1] == 1 {
+                    return false
+                }
+            }
+        }
+        
+        return true
+    }
+    
+    private func pow(_ base: Int, power: Int) -> Int {
+        if base == 0 { return 0 }
+        var result = 1
+        for _ in 0..<power {
+            result *= base
+        }
+        return result
+    }
+}
+
+let s = Solution()
+let r = s.hasAlternatingBits(4)
+print(r)

Easy/693.Binary Number with Alternating Bits.playground/contents.xcplayground

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<playground version='5.0' target-platform='ios' buildActiveScheme='true' importAppTypes='true'>
+    <timeline fileName='timeline.xctimeline'/>
+</playground>

Easy/693.Binary Number with Alternating Bits.playground/playground.xcworkspace/contents.xcworkspacedata

@@ -83,7 +83,7 @@
 79. [Sum of Left Leaves](https://github.com/recherst/leetcode-algtorithm/blob/main/Easy/404.Sum%20of%20Left%20Leaves.playground/Contents.swift)
 80. [Convert a Number to Hexadecimal](https://github.com/recherst/leetcode-algtorithm/blob/main/Easy/405.Convert%20a%20Number%20to%20Hexadecimal.playground/Contents.swift)
 81. [Longest Palindrome](https://github.com/recherst/leetcode-algtorithm/blob/main/Easy/409.Longest%20Palindrome.playground/Contents.swift)
-82. [Fizz Buzz](https://github.com/recherst/leetcode-algtorithm/blob/main/Easy/409.Fizz%20Buzz.playground/Contents.swift)
+82. [Fizz Buzz](https://github.com/recherst/leetcode-algtorithm/blob/main/Easy/412.Fizz%20Buzz.playground/Contents.swift)
 83. [Third Maximum Number](https://github.com/recherst/leetcode-algtorithm/blob/main/Easy/414.Third%20Maximum%20Number.playground/Contents.swift)
 84. [Add Strings](https://github.com/recherst/leetcode-algtorithm/blob/main/Easy/415.Add%20Strings.playground/Contents.swift)
 85. [Number of Segments in a String](https://github.com/recherst/leetcode-algtorithm/blob/main/Easy/434.Number%20of%20Segments%20in%20a%20String.playground/Contents.swift)
@@ -123,6 +123,7 @@
 119. [Longest Continuous Increasing Subsequence](https://github.com/recherst/leetcode-algtorithm/blob/main/Easy/674.Longest%20Continuous%20Increasing%20Subsequence.playground/Contents.swift)
 120. [Valid Palindrome II](https://github.com/recherst/leetcode-algtorithm/blob/main/Easy/680.Valid%20Palindrome%20II.playground/Contents.swift)
 121. [Baseball Game](https://github.com/recherst/leetcode-algtorithm/blob/main/Easy/682.Baseball%20Game.playground/Contents.swift)
+122. [Binary Number with Alternating Bits](https://github.com/recherst/leetcode-algtorithm/blob/main/Easy/693.Binary%20Number%20with%20Alternating%20Bits.playground/Contents.swift)
 
 #### Medium