I have a file with roughly 2 million lines like this:
2s,3s,4s,5s,6s 100000
2s,3s,4s,5s,8s 101
2s,3s,4s,5s,9s 102
The first comma separated part indicates a poker result in Omaha, while the latter score is an example "value" of the cards. It is very important for me to read this file as fast as possible in C++, but I cannot seem to get it to be faster than a simple approach in Python (4.5 seconds) using the base library.
Using the Qt framework (QHash and QString), I was able to read the file in 2.5 seconds in release mode. However, I do not want to have the Qt dependency. The goal is to allow quick simulations using those 2 million lines, i.e. some_container["2s,3s,4s,5s,6s"]
to yield 100
(though if applying a translation function or any non-readable format will allow for faster reading that's okay as well).
My current implementation is extremely slow (8 seconds!):
std::map<std::string, int> get_file_contents(const char *filename)
{
std::map<std::string, int> outcomes;
std::ifstream infile(filename);
std::string c;
int d;
while (infile.good())
{
infile >> c;
infile >> d;
//std::cout << c << d << std::endl;
outcomes[c] = d;
}
return outcomes;
}
What can I do to read this data into some kind of a key/value hash as fast as possible?
Note: The first 16 characters are always going to be there (the cards), while the score can go up to around 1 million.
Some further informations gathered from various comments:
- sample file: http://pastebin.com/rB1hFViM
- ram restrictions: 750MB
- initialization time restriction: 5s
- computation time per hand restriction: 0.5s