Package g0401_0500.s0437_path_sum_iii

Class Solution

  • All Implemented Interfaces:
    
public final class Solution

    437 - Path Sum III.

    Medium

    Given the root of a binary tree and an integer targetSum, return the number of paths where the sum of the values along the path equals targetSum.

    The path does not need to start or end at the root or a leaf, but it must go downwards (i.e., traveling only from parent nodes to child nodes).

    Example 1:

    Input: root = 10,5,-3,3,2,null,11,3,-2,null,1, targetSum = 8

    Output: 3

    Explanation: The paths that sum to 8 are shown.

    Example 2:

    Input: root = 5,4,8,11,null,13,4,7,2,null,null,5,1, targetSum = 22

    Output: 3

    Constraints:

    • The number of nodes in the tree is in the range [0, 1000].

    • <code>-10<sup>9</sup><= Node.val <= 10<sup>9</sup></code>

    • -1000 &lt;= targetSum &lt;= 1000

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description

    • Field Summary

      Fields 
      Modifier and Type Field Description

    • Constructor Summary

      Constructors 
      Constructor Description
      Solution()

    • Enum Constant Summary

      Enum Constants 
      Enum Constant Description

    • Method Summary

      Modifier and Type Method Description
      final Integer pathSum(TreeNode root, Integer targetSum)
      final Unit helper(TreeNode node, Integer targetSum, Long currSum)

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait