solve implement trie prefix tree

Author: sora0319

implement-trie-prefix-tree/sora0319.java

@@ -0,0 +1,40 @@
+class Trie {
+    Set<String> dict;
+
+    public Trie() {
+        dict = new TreeSet<>();
+    }
+
+    public void insert(String word) {
+        dict.add(word);
+    }
+
+    public boolean search(String word) {
+        if(dict.contains(word)) return true;
+        return false;
+    }
+
+    public boolean startsWith(String prefix) {
+        for(String saved : dict){
+            int count = 0;
+            if(prefix.compareTo(saved) > 0) continue;
+            if(prefix.length() > saved.length()) continue;
+
+            for(int i = 0; i < prefix.length(); i++){
+                if(prefix.charAt(i) != saved.charAt(i)) break;
+                count++;
+            }
+            if(count == prefix.length()) return true;
+        }
+        return false;
+    }
+}
+
+/**
+ * Your Trie object will be instantiated and called as such:
+ * Trie obj = new Trie();
+ * obj.insert(word);
+ * boolean param_2 = obj.search(word);
+ * boolean param_3 = obj.startsWith(prefix);
+ */
+