The path sum is judged whether there is to the leaf node and the sum is equal to a certain value
/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode() {}
* TreeNode(int val) { this.val = val; }
* TreeNode(int val, TreeNode left, TreeNode right) {
* this.val = val;
* this.left = left;
* this.right = right;
* }
* }
*/
class Solution {
public boolean hasPathSum(TreeNode root, int targetSum) {
if(root==null){
return false;
}
return hasPathSumHelp(root, targetSum);
}
public boolean hasPathSumHelp(TreeNode root, int targetSum){
if(root==null){
return false;
}
if(root.left==null&&root.right==null&&root.val==targetSum){
return true;
}
return hasPathSumHelp(root.left, targetSum-root.val)||hasPathSumHelp(root.right, targetSum-root.val);
}
}