solve problem Map Sum Pairs

Author: P-ppc

README.md

@@ -240,6 +240,7 @@ All solutions will be accepted!
 |114|[Flatten Binary Tree To Linked List](https://leetcode-cn.com/problems/flatten-binary-tree-to-linked-list/description/)|[java/py/js](./algorithms/FlattenBinaryTreeToLinkedList)|Medium|
 |284|[Peeking Iterator](https://leetcode-cn.com/problems/peeking-iterator/description/)|[java/py](./algorithms/PeekingIterator)|Medium|
 |328|[Odd Even Linked List](https://leetcode-cn.com/problems/odd-even-linked-list/description/)|[java/py/js](./algorithms/OddEvenLinkedList)|Medium|
+|677|[Map Sum Pairs](https://leetcode-cn.com/problems/map-sum-pairs/description/)|[java/py/js](./algorithms/MapSumPairs)|Medium|
 
 # Database
 |#|Title|Solution|Difficulty|

algorithms/MapSumPairs/README.md

@@ -0,0 +1,2 @@
+# Map Sum Pairs
+This problem is easy to solve by Trie

algorithms/MapSumPairs/Solution.java

@@ -0,0 +1,59 @@
+class MapSum {
+    
+    private class TrieNode {
+        public Map<Character, TrieNode> children;
+        public Integer val;
+        
+        public TrieNode () {
+            children = new HashMap<Character, TrieNode>();
+            val = null;
+        }
+    }
+    
+    private TrieNode root;
+    /** Initialize your data structure here. */
+    public MapSum() {
+        root = new TrieNode();
+    }
+    
+    public void insert(String key, int val) {
+        TrieNode node = root;
+        for (char c : key.toCharArray()) {
+            if (node.children.get(c) == null) {
+                node.children.put(c, new TrieNode());
+            }
+            node = node.children.get(c);
+        }
+        node.val = val;
+    }
+    
+    public int sum(String prefix) {
+        int sum = 0;
+        TrieNode node = root;
+        
+        for (char c : prefix.toCharArray()) {
+            if (node.children.get(c) == null) {
+                return 0;
+            }
+            node = node.children.get(c);
+        }
+        
+        sum += node.val == null ? 0 : node.val;
+        List<TrieNode> stack = new ArrayList<TrieNode>(node.children.values());
+        
+        while (stack.size() > 0) {
+            node = stack.remove(0);
+            stack.addAll(node.children.values());
+            sum += node.val == null ? 0 : node.val; 
+        }
+        
+        return 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);
+ */

algorithms/MapSumPairs/solution.js

@@ -0,0 +1,64 @@
+/**
+ * Initialize your data structure here.
+ */
+var MapSum = function() {
+    this.root = new TrieNode()
+};
+
+var TrieNode = function() {
+    this.children = {}
+    this.val = null
+}
+
+/** 
+ * @param {string} key 
+ * @param {number} val
+ * @return {void}
+ */
+MapSum.prototype.insert = function(key, val) {
+    let node = this.root
+    
+    for (let i = 0; i < key.length; i++) {
+        let char = key[i]
+        if (node.children[char] === undefined) {
+            node.children[char] = new TrieNode()
+        }
+        node = node.children[char]
+    }
+    
+    node.val = val
+};
+
+/** 
+ * @param {string} prefix
+ * @return {number}
+ */
+MapSum.prototype.sum = function(prefix) {
+    let sum = 0,
+        node = this.root
+    
+    for (let i = 0; i < prefix.length; i++) {
+        let char = prefix[i]
+        if (node.children[char] === undefined) {
+            return 0
+        }
+        node = node.children[char]
+    }
+    
+    sum += node.val ? node.val : 0
+    let stack = Object.values(node.children)
+    while (stack.length > 0) {
+        node = stack.pop()
+        stack = stack.concat(Object.values(node.children))
+        sum += node.val ? node.val : 0
+    }
+    
+    return sum
+};
+
+/** 
+ * Your MapSum object will be instantiated and called as such:
+ * var obj = Object.create(MapSum).createNew()
+ * obj.insert(key,val)
+ * var param_2 = obj.sum(prefix)
+ */

algorithms/MapSumPairs/solution.py

@@ -0,0 +1,59 @@
+class MapSum(object):
+    
+    class TrieNode(object):
+        def __init__(self, char):
+            self.char = char
+            self.children = {}
+            self.val = None
+    
+    def __init__(self):
+        """
+        Initialize your data structure here.
+        """
+        self.root = self.TrieNode(None)
+
+    def insert(self, key, val):
+        """
+        :type key: str
+        :type val: int
+        :rtype: void
+        """
+        node = self.root
+        for c in key:
+            if node.children.get(c) == None:
+                node.children[c] = self.TrieNode(c)
+            node = node.children[c]
+        node.val = val
+
+    def sum(self, prefix):
+        """
+        :type prefix: str
+        :rtype: int
+        """
+        sm = 0
+        node = self.root
+        
+        for c in prefix:
+            if node.children.get(c) == None:
+                return 0
+            node = node.children[c]
+            
+        sm += node.val if node.val else 0
+        
+        stack = node.children.values()
+        while len(stack) > 0:
+            node = stack.pop()
+            stack += node.children.values()
+            sm += node.val if node.val else 0
+        
+        # or use recursive
+        # for key in node.children:
+        #    sm += self.sum(prefix + key)
+        
+        return sm
+
+
+# Your MapSum object will be instantiated and called as such:
+# obj = MapSum()
+# obj.insert(key,val)
+# param_2 = obj.sum(prefix)