Create 677.Map-Sum-Pairs-My-SubmissionsBack-to-Contest.cpp

Trie/677.Map-Sum-Pairs-My-SubmissionsBack-to-Contest/677.Map-Sum-Pairs-My-SubmissionsBack-to-Contest.cpp

@@ -0,0 +1,65 @@
+class MapSum {
+    class TrieNode
+    {
+        public:
+        TrieNode* next[26];
+        int val;
+        TrieNode()
+        {
+            for (int i=0; i<26; i++)
+                next[i]=NULL;
+            val=0;
+        }
+    };
+    TrieNode* root;
+public:
+    /** Initialize your data structure here. */
+    MapSum() 
+    {
+        root=new TrieNode();
+    }
+
+    void insert(string key, int val) 
+    {
+        TrieNode* node=root;
+        for (int i=0; i<key.size(); i++)
+        {
+            char ch=key[i];
+            if (node->next[ch-'a']==NULL)
+                node->next[ch-'a']=new TrieNode();
+            node=node->next[ch-'a'];
+        }
+        node->val=val;
+    }
+
+    int sum(string prefix) 
+    {
+        TrieNode* node=root;
+        for (int i=0; i<prefix.size(); i++)
+        {
+            char ch=prefix[i];
+            if (node->next[ch-'a']==NULL)
+                node->next[ch-'a']=new TrieNode();
+            node=node->next[ch-'a'];
+        }
+        int SUM=0;
+        DFS(node,SUM);
+        return SUM;
+    }
+
+    void DFS(TrieNode* node, int & SUM)
+    {
+        if (node==NULL) return;
+
+        SUM+=node->val;
+        for (int i=0; i<26; i++)
+            DFS(node->next[i],SUM);
+    }
+};
+
+/**
+ * Your MapSum object will be instantiated and called as such:
+ * MapSum obj = new MapSum();
+ * obj.insert(key,val);
+ * int param_2 = obj.sum(prefix);
+ */