Recently, I came across this snippet of code:

#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
typedef tree<int,null_type,less<int>,rb_tree_tag, tree_order_statistics_node_update> indexed_set;

which implements a policy based data structure. Yet when I ran it on VS code on my Mac(pls don't judge), the code kept on giving me errors stating that "assoc_container.hpp not found" ect.. I searched online for the source code for the ext folder that assoc_container is located in yet the only thing that I could find is this link which doesn't contain a pb_ds folder. For the people who use policy based data structures, do you guys know whether there is anything I can do so that I'm able to implement these policy based data structures?

PS:I've looked at this blog post Post,but I wasn't gain a verifiable answer on what to do since I'm small brained. I also compile my code with "gcc --std=c++17 $x -o $lol" where $x is the file name of the cpp file and $lol is the output file name.