Compile Error
/in/BSTsequence.cpp: In member function 'void BST::dfs(std::deque<BST::Node*>&, std::vector<int>&, int&)':
/in/BSTsequence.cpp:38:23: error: conversion to 'int' from 'std::deque<BST::Node*>::size_type {aka long unsigned int}' may alter its value [-Werror=conversion]
int size = dq.size();
~~~~~~~^~
cc1plus: all warnings being treated as errors
