leetcode：leetcode ：Path Sum

<span style="font-size:18px;">/**
* Definition for binary tree
* public class TreeNode {
*     int val;
*     TreeNode left;
*     TreeNode right;
*     TreeNode(int x) { val = x; }
* }
*/
public class Solution {
static int ans = 0;
// static int sum = 0;
static boolean flag = false;
public boolean hasPathSum(TreeNode root, int sum) {
ans = 0;
flag = false;
traverl(root, sum);
return flag;
}
public static boolean isLeaf(TreeNode root){
return root.left == null && root.right == null;
}

public static void  traverl(TreeNode root, int sum){
if(root != null && !flag){
ans += root.val;
if(isLeaf(root) && sum == ans){
flag = true;
}
traverl(root.left, sum);
traverl(root.right, sum);
ans -= root.val;
}
}

}
</span>