encode and decode strings solution

Author: hyunolike

encode-and-decode-strings/hyunolike.java

@@ -0,0 +1,38 @@
+public class Codec {
+
+    // Encodes a list of strings to a single string.
+    public String encode(List<String> strs) {
+        StringBuilder sb = new StringBuilder();
+
+        for (String s : strs) {
+            sb.append(s.length()).append('#').append(s);
+        }
+
+        return sb.toString();
+    }
+
+    // Decodes a single string to a list of strings.
+    public List<String> decode(String s) {
+        List<String> res = new ArrayList<>();
+        int i = 0;
+
+        while (i < s.length()) {
+            int j = i;
+
+            // find '#'
+            while (s.charAt(j) != '#') {
+                j++;
+            }
+
+            int length = Integer.parseInt(s.substring(i, j));
+            j++; // move past '#'
+
+            String word = s.substring(j, j + length);
+            res.add(word);
+
+            i = j + length; // move to next encoded segment
+        }
+
+        return res;
+    }
+}