Whats the difference between these 2
map.lower_bound(val) vs lower_bound(map.begin(),map.end(),val)
i was getting tle on https://codeforces.com/contest/1902/submission/239546603
correct on https://codeforces.com/contest/1902/submission/239546733
with just 1 line change
TLE -> auto it = lb(mp2[(p4.fi+n)][p4.se].begin(), mp2[(p4.fi+n)][p4.se].end(), l-1);
CORRECT -> auto it=mp2[(p4.fi+n)][p4.se].lb(l-1);
A similar answer for std::set is here.
see this
Short answer -> If you are using a data structure like a set or map always use their own implementation of lower_bound() they are faster, probably because of some internal implementation.
For arrays and vectors you can use the normal lower bound. My guess is that it has something to do with the accessing time of the elements while performing the operations.