leetcode

commit b375dbd77fd05aaa8a5b621816cb041084cdbdd3
parent ef5380526d0b959417df9972bc1d385ee29c258c
Author: AndrewLockVI <andrewlaack1@gmail.com>
Date:   Fri, 21 Apr 2023 01:01:40 -0500

Completed path sum problem using dart

Diffstat:
A
path-sum/path-sum.dart
 | 
30
++++++++++++++++++++++++++++++

1 file changed, 30 insertions(+), 0 deletions(-)
diff --git a/path-sum/path-sum.dart b/path-sum/path-sum.dart
@@ -0,0 +1,30 @@
+//Find if there is a path down a binary tree where all of the vals
+//added together is equal to the targetSum. 
+//The time complexity of this is O(n) because in the worst case 
+//the algorithm will visit all nodes.
+
+
+class Solution {
+  int goal = 0;
+  bool found = false;
+  bool hasPathSum(TreeNode? root, int targetSum) {
+      goal = targetSum;
+      recurse(root, 0);
+      return found;
+  }
+  void recurse(TreeNode? node, int current_val){
+      current_val += node?.val ?? 0;
+      if(node == null){
+          return;
+      }
+      if(found == true){
+          return;
+      }
+      if(current_val == goal && node.left == null && node.right == null){
+          found = true;
+          return;
+      }
+      recurse(node?.left , current_val);
+      recurse(node?.right, current_val);
+  }
+}