on android, the vector permutation overflow problem

Question

I use next_permutation function to have a vector list permutation, but the stack is overflow when running the program, due to size of the vector

#include <vector>
#include <algorithm>

 vector<int> uuid_list_index;
vector<vector<int>> permutation_uuid_lists;
        for(size_t i=0; i<12; i++)
        {
            uuid_list_index.push_back(i);
        }
        do permutation_uuid_lists.push_back(uuid_list_index);
        while(next_permutation(uuid_list_index.begin(), uuid_list_index.end()));

when run the program, the binary overflow crash, How implement a permutation function for list {0,1,2,3,4,5,6,7,8,9,10,11,12}?

FYI: https://stackoverflow.com/questions/1452721/why-is-using-namespace-std-considered-bad-practice — Thomas Weller, Jan 09 '23 at 11:50

score 3 · Accepted Answer · answered Jan 09 '23 at 11:57

This is not too surprising at all. uuid_list_index has 12 different entries.

The number of permutations of a sequence of length N is N!; and
12! = 479001600.

permutation_uuid_lists contains more than 479 million std::vector<int>s; since each vector has at least a 12 Byte header (armv8) and contains a pointer to at least 12× 4-byte integer memory elements, plus implies a 16-byte entry in a memory allocation table: you're trying to use around 30 GB of RAM. That's more than your phone has.

on android, the vector permutation overflow problem

1 Answers1