add: encode and decode

Author: Yongseok-Choi-dev

encode-and-decode-strings/Solution.java

@@ -0,0 +1,45 @@
+import java.util.ArrayList;
+import java.util.List;
+
+public class Solution {
+    /*
+     * @param strs: a list of strings
+     * @return: encodes a list of strings to a single string.
+     */
+    public String encode(List<String> strs) {
+        List<String> temp = new ArrayList<>();
+
+        if(strs.size() == 0) return null;
+
+        for(String s : strs) {
+            if(":".equals(s)) {
+                temp.add("::");
+            } else {
+                temp.add(s);
+            }            
+        }
+
+        return String.join(":;", temp);
+    }
+
+    /*
+     * @param str: A string
+     * @return: decodes a single string to a list of strings
+     */
+    public List<String> decode(String str) {
+        List<String> temp = new ArrayList<>();
+
+        if(str == null) return new ArrayList<>();
+
+        // if(str.length() == 0) return new ArrayList<>();
+        
+        for(String s : str.split(":;")) {
+            if("::".equals(s)) {
+                temp.add(":");
+            } else {
+                temp.add(s);
+            }            
+        }
+        return temp;
+    }
+}