Now a days if you work in an software industry (Service based, product based) with highly skilled programmers, good experienced team, expert frameworks, you learn only to code into that project.
They interview candidates like they will recruit you in R&D division of their organisation to develop some high scale complex project. But usually this never happens.
So we never learn actually problem solving things via core programming because of extensive use of frameworks. You have to learn by yourself in core programming languages.
Don’t use any inbuilt function(i.e. array and strings inbuilt complex function) of a language to solve problems except basic library functions such as count, length, ceil, floor etc.
First thing first, be confident as you know all about programming required to code/program. you have read all data structures, many programming languages in your academics.
Now only thing remaining is practice. There are numbers of website to practice from beginner to expert such as:
and again practice at least 2 to 3 hours on daily basis to become an artist in programming.
You can go through some books also to brush up your data structure and algorithm skills such as introduction to algorithms by Cormen.