This thing has been said many times already on codeforces. Just replace all $$$\le$$$ with $$$<$$$ in your comparators (func and func2). (It's called strict weak ordering which STL algorithms expect, you may google more about it)

BTW, you have a really bizzare coding style. You almost never need to use unsigned data types to solve a problem as almost all problems have constraints in such a way that the values fit in a signed data types. Also, thinking whether to use unsigned or signed data type might also take a lot of time and is also prone to errors. So, please avoid using unsigned data types especially for solving CF problems.