I can confirm it can be solved.

Excellent. I will try it out soon. Im working right now on an more efficient solution. I will try it with the old program which could solve in time until it reached 10x10 and the newer potentially faster one.

I will also double check it again. Maybe it was an error in the program.

Sounds great. I could find 2 11by11 Puzzles somewhere in the internet and used them for my unit tests.

Yes I read about that. In the meantime I discussed my solution with some people and we came up that it is not that efficient yet. I try now an completly different approach to solve the puzzles faster. We will see If thats enough for the tests.

According to the Test I can solve test for Size 10 in ~500ms. But then I always get a time out for cases with size = 11.

I also run tests on my machine and can run all test including 11 in less than 4 seconds. Still these time outs appear.

I already try for days with crazy optimizations to make the code faster and start to wonder if its a test suite issue.

Right now I feelt his way harder than the 1 Kyu 7by7.

Please Check it it is still solveable.

any good ressources to find 10x10 and 11x11 puzzles with solution for the unit tests?

could not find any in the internet.

The last two test cases provided are broken:

{
	{
		{ 0, 0, 0, 0, 0, 3, 0 },
		{ 0, 1, 0, 0, 0, 0, 0 },
		{ 0, 0, 0, 0, 0, 0, 0 },
		{ 0, 0, 0, 5, 0, 0, 0 },
		{ 0, 0, 0, 7, 0, 0, 0 },
		{ 4, 0, 0, 2, 0, 0, 0 },
		{ 0, 0, 2, 0, 0, 0, 0}

	},
	{
		{ 5, 7, 6, 4, 2, 3, 1 },
		{ 3, 1, 5, 6, 4, 2, 7 },
		{ 2, 3, 7, 1, 6, 5, 4 },
		{ 6, 2, 1, 5, 7, 4, 3 },
		{ 1, 5, 4, 7, 3, 6, 2 },
		{ 4, 6, 3, 2, 1, 7, 5 },
		{ 7, 4, 2, 3, 5, 1, 6}

	},
	{ 
		{ 3, 1, 2, 3, 4, 4, 2, 5, 1, 4, 3, 3, 2, 2, 2, 2, 2, 2, 4, 3, 1, 1, 3, 3, 2, 3, 4, 2 }
	}
},
{
	{
		{ 0, 0, 0, 0, 0, 3, 0 },
		{ 0, 1, 0, 0, 0, 0, 0 },
		{ 0, 0, 0, 0, 0, 0, 0 },
		{ 0, 0, 0, 5, 0, 0, 0 },
		{ 0, 0, 0, 7, 0, 0, 0 },
		{ 4, 0, 0, 2, 0, 0, 0 },
		{ 0, 0, 2, 0, 0, 0, 0}

	},
	{
		{ 5, 7, 6, 4, 2, 3, 1 },
		{ 3, 1, 5, 6, 4, 2, 7 },
		{ 2, 3, 7, 1, 6, 5, 4 },
		{ 6, 2, 1, 5, 7, 4, 3 },
		{ 1, 5, 4, 7, 3, 6, 2 },
		{ 4, 6, 3, 2, 1, 7, 5 },
		{ 7, 4, 2, 3, 5, 1, 6}

	},
	{ 
		{ 3, 1, 2, 3, 4, 4, 2, 5, 1, 4, 3, 3, 2, 2, 2, 2, 2, 2, 4, 3, 1, 1, 3, 3, 2, 3, 4, 2 }
	}
}

There is no valid solution

Wow after optimizing my C++ solution I got it from ~40ms per solve to ~2ms.I think im ready for 7x7. Im happy with the code it is readable and fast but quite long. Wonder whats the speed record here.

I would love to see a c++ version. Is it right if I sole it in Python I could translate it too C++ after?

For C++ the function signature should be really changed to:

std::array<std::array<int>,4>, 4> SolvePuzzle (std::array<int, 16>& clues) 

Nobody in modern C++ would use pointer parameters like int** for an function parameter.

() can be omitted