I have been a Codechef user for past 1-2 years, and I am finding the Contest problems extremely difficult to solve. Maximum I am able to get only one or two correct, most of the time I get either WA Wrong Answer or TLE (Time Limit Exceeded). A few times, I am able to get the logic behind the problem and the test outputs, and I try for some other inputs and then also it works. Everything seems to be fine, but still the Codechef system tells it is either WA or taking too much time. I am getting frustrated, maybe I need to start with the practice problems first. But i do not know what level of practice problems should I start solving.
I have some knowledge about data structures, (like basic structures like arrays, stacks queues, linked lists and trees (simple trees not AVL trees or such stuff), basic sorting, graphs, algorithmic approaches like divide and conquer, dynamic programming, I donot know advanced things like Hash Tables, and I code in C/ C++.
SO could someone tell me from where to start ? What level of practice problems or sample problems would be appropriate for my level.