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Java-based LeetCode algorithm problem solutions, regularly updated

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package g0101_0200.s0112_path_sum;

// #Easy #Depth_First_Search #Breadth_First_Search #Tree #Binary_Tree #Data_Structure_I_Day_12_Tree
// #2022_06_23_Time_0_ms_(100.00%)_Space_43.8_MB_(36.11%)

import com_github_leetcode.TreeNode;

/*
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode() {}
 *     TreeNode(int val) { this.val = val; }
 *     TreeNode(int val, TreeNode left, TreeNode right) {
 *         this.val = val;
 *         this.left = left;
 *         this.right = right;
 *     }
 * }
 */
/**
 * 112 - Path Sum\.
 *
 * Easy
 *
 * Given the `root` of a binary tree and an integer `targetSum`, return `true` if the tree has a **root-to-leaf** path such that adding up all the values along the path equals `targetSum`.
 *
 * A **leaf** is a node with no children.
 *
 * **Example 1:**
 *
 * ![](https://assets.leetcode.com/uploads/2021/01/18/pathsum1.jpg)
 *
 * **Input:** root = [5,4,8,11,null,13,4,7,2,null,null,null,1], targetSum = 22
 *
 * **Output:** true 
 *
 * **Example 2:**
 *
 * ![](https://assets.leetcode.com/uploads/2021/01/18/pathsum2.jpg)
 *
 * **Input:** root = [1,2,3], targetSum = 5
 *
 * **Output:** false 
 *
 * **Example 3:**
 *
 * **Input:** root = [1,2], targetSum = 0
 *
 * **Output:** false 
 *
 * **Constraints:**
 *
 * *   The number of nodes in the tree is in the range `[0, 5000]`.
 * *   `-1000 <= Node.val <= 1000`
 * *   `-1000 <= targetSum <= 1000`
**/
public class Solution {
    public boolean hasPathSum(TreeNode root, int sum) {
        if (root == null) {
            return false;
        }
        if (sum == root.val && root.left == null && root.right == null) {
            return true;
        }
        return hasPathSum(root.left, sum - root.val) || hasPathSum(root.right, sum - root.val);
    }
}