Merge pull request #2014 from Zhaoshan-Duan/encode-and-decode-strings

Create: 0217-encode-and-decode-strings.kt

Author: a93a

kotlin/0217-encode-and-decode-strings.kt

@@ -0,0 +1,38 @@
+class Codec {
+    // Encodes a list of strings to a single string.
+    fun encode(strs: List<String>): String {
+        var res = ""
+        strs.forEach{
+            res = res + it.length + "#" + it
+        }
+        return res
+    }
+    
+    // Decodes a single string to a list of strings.
+    fun decode(s: String): List<String> {
+        var (res, i) = Pair(mutableListOf<String>(), 0)
+        
+        while (i < s.length){
+            var j = i
+            while (s[j] != '#') {
+                j++
+            }
+            val lengthOfWord = s.subSequence(i, j).toString().toInt()
+            
+            val (wordStart, wordEnd) = Pair(j+1, j+1+lengthOfWord)
+            res.add(s.subSequence(wordStart, wordEnd).toString())
+
+            i = wordEnd
+
+        }
+        return res
+        
+    }
+}
+
+/**
+ * Your Codec object will be instantiated and called as such:
+ * var obj = Codec()
+ * val s = obj.encode(strs)
+ * val ans = obj.decode(s)
+ */