bool HasPathSum(TreeNode root, int sum) {

			bool ret=false;

			if(root==null)return false;

			if(root.left==null&&root.right==null) return root.val==sum;

			if(root.left!=null)

			{

				ret=ret|| HasPathSum(root.left,sum-root.val);

			}

			if(root.right!=null)

			{

				ret=ret|| HasPathSum(root.right,sum-root.val);

			}

			return ret;

		}

bool HasPathSum(TreeNode root, int sum) {

			bool ret=false;

			if(root==null)return false;

			if(root.left==null&&root.right==null) return root.val==sum;

			if(root.left!=null)

			{

				root.left.val+=root.val;

				ret=ret|| HasPathSum(root.left,sum);

			}

			if(root.right!=null)

			{

				root.right.val+=root.val;

				ret=ret|| HasPathSum(root.right,sum);

			}

			return ret;

		}