题解 | #二叉树中和为某一值的路径(一)#

import java.util.*;

/*
 * 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);
    }

    private boolean dfs(TreeNode cur, int target) {
        if (cur == null) {
            return false;
        }
        target -= cur.val;
        if (cur.left == null && cur.right == null && target == 0) {
            return true;
        }
        return dfs(cur.left, target) || dfs(cur.right, target);
    }
}