题解 | #二叉树中和为某一值的路径(一)#

/*
 * public class TreeNode {
 *   int val = 0;
 *   TreeNode left = null;
 *   TreeNode right = null;
 * }
 */

public class Solution {
    /**
     * 
     * @param root TreeNode类 
     * @param sum int整型 
     * @return bool布尔型
     */
    public boolean hasPathSum (TreeNode root, int sum) {
        // write code here
        if(root == null && sum == 0){
            return false;
        }
        if(root == null){
            return false;
        }
        int result = root.val;
        
        if(root.left == null &&root.right == null && result == sum){
            return true;
        }
        return hasPathSum(root.left, sum - result) || hasPathSum(root.right, sum - result);
    }
}