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Path Sum
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) { if(null == root) return false; sum = sum - root.val; if(null == root.left && null == root.right) { if(sum ==0) return true; else return false; }else{ return hasPathSum(root.left, sum) || hasPathSum(root.right, sum); } }} 转载地址：http://jnuni.baihongyu.com/