add design add and search words data structure solution

Author: Tessa1217

design-add-and-search-words-data-structure/Tessa1217.java

@@ -0,0 +1,79 @@
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ *  WordDictionary
+ * WordDictionary() - 객체 초기화
+ * void addWord(word) - 자료 구조에 word 추가
+ * boolean search(word) - 자료 구조에 word 있으면 true 아니면 false 반환
+ - '.'는 와일드카드로 활용 가능
+ */
+class WordDictionary {
+
+    private Node root;
+
+    public WordDictionary() {
+        root = new Node();
+    }
+
+    public void addWord(String word) {
+        Node current = root;
+        for (char c : word.toCharArray()) {
+            if (!current.nodeCharacters.containsKey(c)) {
+                current.nodeCharacters.put(c, new Node());
+            }
+            current = current.nodeCharacters.get(c);
+        }
+        current.isEnd = true;
+    }
+
+    public boolean search(String word) {
+        return searchInNode(word, 0, root);
+    }
+
+    private boolean searchInNode(String word, int idx, Node node) {
+
+        if (node == null) {
+            return false;
+        }
+
+        if (idx == word.length()) {
+            return node.isEnd;
+        }
+
+        char c = word.charAt(idx);
+        // 와일드카드는 Node에 있는 전체 값 다 탐색
+        if (c == '.') {
+            for (Node child : node.nodeCharacters.values()) {
+                if (searchInNode(word, idx + 1, child)) {
+                    return true;
+                }
+            }
+            return false;
+        } else {
+            Node current = node.nodeCharacters.get(c);
+            return searchInNode(word, idx + 1, current);
+        }
+    }
+
+    static class Node {
+
+        boolean isEnd;
+
+        Map<Character, Node> nodeCharacters;
+
+        Node() {
+            nodeCharacters = new HashMap<>();
+            isEnd = false;
+        }
+
+    }
+}
+
+/**
+ * Your WordDictionary object will be instantiated and called as such:
+ * WordDictionary obj = new WordDictionary();
+ * obj.addWord(word);
+ * boolean param_2 = obj.search(word);
+ */
+