469.Identical Binary Tree

1.Description(Easy)

Check if two binary trees are identical. Identical means the two binary trees have the same structure and every identical position has the same value.

Example

    1             1
   / \           / \
  2   2   and   2   2
 /             /
4             4

are identical.

    1             1
   / \           / \
  2   3   and   2   3
 /               \
4                 4

are not identical.

2.Code

 public boolean isIdentical(TreeNode a, TreeNode b) {
        if (a == null && b == null ) return true;
        else if (a == null) return false;
        else if (b == null) return false;
        if (a.val != b.val) return false;
        return isIdentical(a.left, b.left) && isIdentical(a.right, b.right);
    }