add 0938 cpp version(40ms)

Author: zouwx2cs

solution/0938.Range Sum of BST/Solution.cpp

@@ -1,30 +1,47 @@
-# Definition for a binary tree node.
-# class TreeNode:
-#     def __init__(self, x):
-#         self.val = x
-#         self.left = None
-#         self.right = None
+/**
+ * Definition for a binary tree node.
+ * struct TreeNode {
+ *     int val;
+ *     TreeNode *left;
+ *     TreeNode *right;
+ *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
+ * };
+ */
+class Solution {
+public:
+    int rangeSumBST(TreeNode* root, int L, int R) {
+        if (nullptr == root)
+            return 0 ;
+        stack<TreeNode *> s ;
+        s.push(root) ;
+        int sum = 0 ;
+        while (!s.empty())
+        {
+            TreeNode *node = s.top() ;
+            s.pop() ;
+            
+            if (nullptr == node)
+                continue ;
+            
+            if (node->val > R)
+                s.push(node->left) ;
+            else if (node->val < L)
+                s.push(node->right) ;
+            else
+            {
+                sum += node->val ;
+                s.push(node->left) ;
+                s.push(node->right) ;
+            }
+        }
+        
+        return sum ;
+    }
+};
 
-
-class Solution:
-    def rangeSumBST(self, root, L, R):
-        """
-        :type root: TreeNode
-        :type L: int
-        :type R: int
-        :rtype: int
-        """
-        def searchBST(node):
-            if not node:
-                return
-            if L <= node.val <= R:
-                self.ans += node.val
-                searchBST(node.right)
-                searchBST(node.left)
-            elif node.val < L:
-                searchBST(node.right)
-            elif node.val > R:
-                searchBST(node.left)
-        self.ans = 0
-        searchBST(root)
-        return self.ans
+static int x = []()
+{
+    ios::sync_with_stdio(false); 
+    cin.tie(nullptr); 
+    return 0; 
+}() ;

solution/0953.Verifying an Alien Dictionary/Solution.cpp

@@ -20,8 +20,7 @@
 
     bool cmp(string a, string b) 
     {
-        int i ;
-        int len = min(a.size(), b.size()) ;
+        int i, len = min(a.size(), b.size()) ;
         for (i = 0; i < len; ++i)
         {
             int c = ala[ a[i] - 'a' ] - ala[ b[i] - 'a' ] ;
@@ -31,9 +30,6 @@
                 return false ;
         }
 
-        if (i == a.size())
-            return true ;
-        else
-            return false ;
+        return i == a.size() ;
     }
 };