using sed

Consider the following file called swap.txt:

349 230 481

800 456 129

043 942 584

901 627 874

Each three-digit number is separated by a space. Write a one-line sed command that performs in-place substitution to swap the first digit with the third digit of the first number in every line. For example, after running the appropriate sed command, the swap.txt file would contain:

943 230 481

008 456 129

340 942 584

109 627 874

For bonus, can you swap the first digit with the third digit of the second number in every line? Do not worry about performing in-place substitution for this part. For example, after running the appropriate sed command, the following would be output to the terminal:

349 032 481

800 654 129

043 249 584

901 726 874