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
       return dfs(root,sum);
    }
    public boolean dfs(TreeNode root,int tar){
        if(root == null){
            return false;
        }
        tar = tar - root.val;
        if(tar == 0 && root.left == null && root.right == null){
            return true;
        }
        return dfs(root.left,tar) || dfs(root.right,tar);
    }
}