import java.util.*;
public class Solution {
/**
*
* @param root TreeNode类
* @param sum int整型
* @return bool布尔型
*/
public boolean hasPathSum (TreeNode root, int sum) {
if(root==null){
return false;
}
return hasPathSumDg(root,0,sum);
}
public boolean hasPathSumDg (TreeNode root, int cur, int sum) {
cur = cur + root.val;
if(root.left==null&&root.right==null){
return cur == sum;
}
if(root.left==null){
return hasPathSumDg(root.right,cur,sum);
}else if(root.right==null){
return hasPathSumDg(root.left,cur,sum);
}else{
return hasPathSumDg(root.left,cur,sum) || hasPathSumDg(root.right,cur,sum);
}
}
}