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: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 binary tree
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
public class Solution {
public boolean hasPathSum(TreeNode root, int sum) {
return pathSum(root,sum,0);
}
public boolean pathSum(TreeNode node,int sum,int path){
if(node==null) return false;
if((node.val+path)==sum && node.left==null && node.right==null) return true;
else return pathSum(node.left,sum,node.val+path)||pathSum(node.right,sum,node.val+path);
}
}思路：递归，注意，题目要求，结尾的必须是叶子节点。原文地址：http://blog.csdn.net/dutsoft/article/details/37737637
