add destructor to trie

Author: caizkun

Algorithm-DataStructure/trie.cpp

@@ -17,6 +17,10 @@ class TrieNode {
     TrieNode(bool status=false) : isComplete(status) {
         children.resize(NUM_ALPHABET);
     }
+    
+    ~TrieNode() {
+        children.clear();
+    }
 };
 
 
@@ -26,6 +30,10 @@ class Trie {
         root = new TrieNode(false);
     }
 
+    ~Trie() {
+        delete root;
+    }
+    
     void insert(string word);
     bool search(string word);
     bool startWith(string prefix);