题解 | #二叉树中和为某一值的路径(一)#

import java.util.*;

public class Solution {
    /**
     * 
     * @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;
        }
        return hasPathSumDg(root,0,sum);
    }
    
    public boolean hasPathSumDg (TreeNode root, int cur, int sum) {
        cur = cur + root.val;
        if(root.left==null&&root.right==null){
           return cur == sum;
        }
        if(root.left==null){
            return hasPathSumDg(root.right,cur,sum);
        }else if(root.right==null){
            return hasPathSumDg(root.left,cur,sum);
        }else{
            return hasPathSumDg(root.left,cur,sum) || hasPathSumDg(root.right,cur,sum);
        }
    }
}