题解 | #二叉树中是否存在节点和为指定值的路径#

import java.util.*;

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

public class Solution {

    boolean flg = false;

    /**
     * 
     * @param root TreeNode类 
     * @param sum int整型 
     * @return bool布尔型
     */
    public boolean hasPathSum (TreeNode root, int sum) {

        if (root == null) {
            return false;
        }

        treeDeep(root, sum);

        return flg;
    }

    public void treeDeep (TreeNode root, int sum) {

        if (root == null) {
            return;
        }

        if (root.left == null && root.right == null && sum - root.val == 0) {
            flg = true;
            return;
        }

        treeDeep(root.left, sum - root.val);

        treeDeep(root.right, sum - root.val);
    }
}