From 80701ab517aee7c4d41e550a97c396caca4c1489 Mon Sep 17 00:00:00 2001
From: moophis <moophis@gmail.com>
Date: Sat, 18 Oct 2014 14:23:24 -0700
Subject: [PATCH] Path Sum: refactor code

---
 Path Sum.cpp | 36 +++++++++---------------------------
 1 file changed, 9 insertions(+), 27 deletions(-)

diff --git a/Path Sum.cpp b/Path Sum.cpp
index 8a73150..9219a52 100644
--- a/Path Sum.cpp	
+++ b/Path Sum.cpp	
@@ -25,38 +25,20 @@
  * };
  */
 class Solution {
-    bool find_path(TreeNode *root, int sum, int cur) {
-        if (root->left == nullptr && root->right == nullptr) {
-            return sum == cur + root->val;
+    bool find_sum(TreeNode *root, const int sum, int cur) {
+        if (root == nullptr) {
+            return false;
         }
         
-        bool left_match = false;
-        bool right_match = false;
-        
-        if (root->left != nullptr) {
-            left_match = find_path(root->left, sum, cur + root->val);
-            if (left_match) {
-                return true;
-            }
+        cur += root->val;
+        if (root->left == nullptr && root->right == nullptr) {
+            return (sum == cur);
         }
-        if (root->right != nullptr) {
-            right_match = find_path(root->right, sum, cur + root->val);
-            if (right_match) {
-                return true;
-            }
-        }  
-        
-        return false;
+        return find_sum(root->left, sum, cur) || find_sum(root->right, sum, cur);
     }
+    
 public:
     bool hasPathSum(TreeNode *root, int sum) {
-        // IMPORTANT: Please reset any member data you declared, as
-        // the same Solution instance will be reused for each test case.
-        if (root == nullptr) {
-            return false;
-        }
-        
-        int cur = 0;
-        return find_path(root, sum, cur);
+        return find_sum(root, sum, 0);
     }
 };
\ No newline at end of file