717.1-bit and 2-bit Characters.

Author: recherst

Easy/717.1-bit and 2-bit Characters.playground/Contents.swift

@@ -0,0 +1,44 @@
+/**
+ We have two special characters:
+
+ - The first character can be represented by one bit 0.
+ - The second character can be represented by two bits (10 or 11).
+ Given a binary array bits that ends with 0, return true if the last character must be a one-bit character.
+
+  
+
+ Example 1:
+ Input: bits = [1,0,0]
+ Output: true
+ Explanation: The only way to decode it is two-bit character and one-bit character.
+ So the last character is one-bit character.
+ 
+ Example 2:
+ Input: bits = [1,1,1,0]
+ Output: false
+ Explanation: The only way to decode it is two-bit character and two-bit character.
+ So the last character is not one-bit character.
+  
+
+ Constraints:
+ - 1 <= bits.length <= 1000
+ - bits[i] is either 0 or 1.
+ */
+class Solution {
+    func isOneBitCharacter(_ bits: [Int]) -> Bool {
+        var result = [Int]()
+        for (i, c) in bits.enumerated() {
+            if c == 0 && i != bits.count - 1 {
+                result.removeAll()
+            } else {
+                result.append(c)
+            }
+        }
+        if result.last != 0 { return false }
+        return (result.count - 1) % 2 == 0
+    }
+}
+
+let s = Solution()
+let r = s.isOneBitCharacter([1, 1, 0, 1, 1, 1, 0, 1, 1, 0])
+print(r)

Easy/717.1-bit and 2-bit Characters.playground/contents.xcplayground

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+<?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/717.1-bit and 2-bit Characters.playground/playground.xcworkspace/contents.xcworkspacedata

@@ -129,6 +129,7 @@
 125. [Long Pressed Name](https://github.com/recherst/leetcode-algtorithm/blob/main/Easy/925.Long%20Pressed%20Name.playground/Contents.swift)
 126. [Binary Search](https://github.com/recherst/leetcode-algtorithm/blob/main/Easy/704.Binary%20Search.playground/Contents.swift)
 127. [To Lower Case](https://github.com/recherst/leetcode-algtorithm/blob/main/Easy/709.To%20Lower%20Case.playground/Contents.swift)
+128. [1-bit and 2-bit Characters](https://github.com/recherst/leetcode-algtorithm/blob/main/Easy/717.1-bit%20and%202-bit%20Characters.playground/Contents.swift)
 
 #### Medium