Worst practice. This solution will not work, for example, if all numbers are equal to 5.

This is not a valid solution!! It will not correctly identify boards with repeated digits. See this issue

I had same idea, but checking if sum is correct does not prevent gibberish summing to 45 though.

Aaaaaaand now I feel stupid with my solution :D

It doesn't work. If you input board full of 5's it prints out true.

Not always sum of all numbers is a correct answer. For example, the sequence can be like: 1 1 1 7 6 7 8 9 5 = 45.

ERROR:

unsigned int example2[9][9] = {{45, 0, 0, 0, 0, 0, 0, 0, 0},
{0, 0, 0, 45,0, 0, 0, 0, 0},
{0, 0, 0, 0, 0, 0, 45, 0, 0},
{0, 45, 0, 0, 0, 0, 0, 0, 0},
{0, 0, 0, 0, 45, 0, 0, 0, 0},
{0, 0, 0, 0, 0, 0, 0, 45,0},
{0, 0, 45, 0, 0, 0, 0, 0, 0},
{0, 0, 0, 0, 0, 45,0, 0, 0},
{0, 0, 0, 0, 0, 0, 0, 0, 45},};

Smart solution indeed!

Yes it's clever but I probably wouldn't hire you as a developer :). Just think of somebody else having to fix a bug or implement a change in code like that!

I really like how you managed checking the blocks with the vector. I was trying to think through how to do it that way it and couldn't see it clearly.

I like it!

It is not enough if you take a valid solution and replace all 2's by 1's and all 8's by 9's, you still get sum 45 but it is not a correct solution.

In description for task written: ...contain all of the digits from 1 to 9.

What for write more than required?

As we are creating a sudoku validator, we can not make assumptions regarding the inputs. We need to take care of all conditions. If you see the example 2 in the question, there are 0s in the sudoku puzzle.