Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the values along the path equals the given sum.
For example:
Given the below binary tree and sum = 22,
5
/ \
4 8
/ / \
11 13 4
/ \ \
7 2 1
return true, as there exist a root-to-leaf path 5->4->11->2 which sum is 22.
/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
public class Solution {
public boolean hasPathSum(TreeNode root, int sum) {
boolean flag=false; if(root==null)
return false; if(root.left==null&&root.right==null&&root.val==sum)
{
flag=true;
return flag;
} if(root.left!=null||root.right!=null)
{
if(root.left!=null&&flag==false)
{
flag=hasPathSum(root.left,sum-root.val);
if(flag==true)
return flag;
} if(root.right!=null&&flag==false)
{
flag=hasPathSum(root.right,sum-root.val);
if(flag==true)
return flag;
} }
return flag;
}
}
4 8
/ / \
11 13 4
/ \ \
7 2 1
return true, as there exist a root-to-leaf path 5->4->11->2 which sum is 22.
代码如下：