add PROGRAMMERS-17684

Author: codejsha

README.md

@@ -23,6 +23,7 @@
 | PROGRAMMERS-12985 :star:  | [java](programmers/problem12985)   | [예상 대진표 (Expected List of Matches)](https://school.programmers.co.kr/learn/courses/30/lessons/12985)                             |
 | PROGRAMMERS-17677         | [java](programmers/problem17677)   | [뉴스 클러스터링 (News Clustering)](https://school.programmers.co.kr/learn/courses/30/lessons/17677)                                  |
 | PROGRAMMERS-17680         | [java](programmers/problem17680)   | [캐시 (Cache)](https://school.programmers.co.kr/learn/courses/30/lessons/17680)                                                       |
+| PROGRAMMERS-17684         | [java](programmers/problem17684)   | [압축 (Compression)](https://school.programmers.co.kr/learn/courses/30/lessons/17684)                                                 |
 | PROGRAMMERS-42577         | [java](programmers/problem42577)   | [전화번호 목록 (List of Phone Numbers)](https://school.programmers.co.kr/learn/courses/30/lessons/42577)                              |
 | PROGRAMMERS-42578         | [python](programmers/problem42578) | [의상 (Clothes)](https://school.programmers.co.kr/learn/courses/30/lessons/42578)                                                     |
 | PROGRAMMERS-42586         | [java](programmers/problem42586)   | [기능개발 (Function Development)](https://school.programmers.co.kr/learn/courses/30/lessons/42586)                                    |

programmers/problem17684/LzwCompression.java

@@ -0,0 +1,47 @@
+package problem17684;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+
+public class LzwCompression {
+    public static void main(String[] args) {
+        var sol = new LzwCompression();
+        var msg1 = "KAKAO";
+        var expected1 = new int[]{11, 1, 27, 15};
+        var result1 = sol.solution(msg1);
+        System.out.println("expected: " + Arrays.toString(expected1) + ", result: " + Arrays.toString(result1));
+    }
+
+    public int[] solution(String msg) {
+        var map = new HashMap<String, Integer>();
+        var index = 0;
+        for (index = 0; index < 26; index++) {
+            map.put(String.valueOf((char) ('A' + index)), index + 1);
+        }
+
+        var list = new ArrayList<Integer>();
+        int i = 0;
+        var j = 1;
+        var temp = "";
+        while (i < msg.length()) {
+            var s = msg.substring(i, j);
+            if (map.containsKey(s)) {
+                temp = s;
+                j++;
+            } else {
+                list.add(map.get(temp));
+                map.put(s, ++index);
+                i += s.length() - 1;
+                j = i + 1;
+            }
+
+            if (j > msg.length()) {
+                list.add(map.get(temp));
+                break;
+            }
+        }
+
+        return list.stream().mapToInt(Integer::intValue).toArray();
+    }
+}