EDIT: Solved. In this problem: 510C - Fox And Names, I get MLE on test case 12. This is strange as I did not allocate that much space.

My solution: https://pastebin.com/LHY3RiAZ

Data Structures: - 2-D Vector of ints - Stack of ints - Vector of bools to check already visited nodes

Functions: - DFS for topological sort, sorted vertices put in stack - DFS for cycle checking

Is there a memory leak or something? I can't tell.

Thanks, Brad.

Maybe it's a stack overflow because your DFS enters an infinite loop. Maybe not.