[WEEK 05] encode and decode strings

Author: sonjs7554

encode-and-decode-strings/essaysir.java

@@ -0,0 +1,38 @@
+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) {
+        StringBuilder sb = new StringBuilder();
+        for (String s : strs) {
+            sb.append(s.length());
+            sb.append('#');
+            sb.append(s);
+        }
+        return sb.toString();
+    }
+
+    /*
+     * @param str: A string
+     * @return: decodes a single string to a list of strings
+     */
+    public List<String> decode(String str) {
+        List<String> res = new ArrayList<>();
+        int i = 0;
+        while (i < str.length()) {
+            // '#' 앞의 숫자를 길이로 파싱
+            int len = 0;
+            while (str.charAt(i) != '#') {
+                len = len * 10 + (str.charAt(i) - '0');
+                i++;
+            }
+            i++; // '#' 건너뛰기
+
+            // 정확히 len 글자만 잘라내기
+            res.add(str.substring(i, i + len));
+            i += len;
+        }
+        return res;
+    }
+}