Please I got Crash(Stack Overflow), I implemented my first heavy-light descomposition and tried this problem, but I got this.

I got AC, I had to  convert the DFS to BFS, to evade the StackOverflow.

Edited by author 02.11.2011 04:45

Edited by author 02.11.2011 07:20

Edited by author 02.11.2011 08:20

{$m 100000000000000000000}

You can use "G++ 9.2 x64" language to avoid it

You can also use
#pragma comment(linker, "/STACK:16777216)
for MSVC

and both heavy-light or sqrt decompositions can be performed with BFS, so no recursion needed