Hello Codeforces community
I have good math contest background (I can solve IMO Shortlist C5-C7 with 60% success rate, went to national Math Olympiad Selection Camp in 2018 summer). However I don't have much CP experience.
What should I do to reach Codeforces Orange and USACO Platinum within christmas ?
Currently I can solve ~1.5 problems (out of 3 problems) in USACO (new) gold within around 1.5 hours and looking at past Codeforces Contests I can solve DIV 2 4-5 problems/ DIV 1 A-B very easily (within 40 minutes) (but I have difficulty implementing them: https://codeforces.com/blog/entry/61899)
I don't have much time to put on informatics since I have Math Olympiad TST's coming up soon.
Div 1 A+B == orange
If you're that good at mathematics you don't need to do much to get to codeforces orange or even red. You said yourself that you have trouble with implementation. Just fix that and getting to yellow will be trivial. After that, just practice solving pure algorithmic problems. Most commonly occuring algorithmic problems are DP, graph and segment tree problems. With that you can easily reach red by first getting to high yellow, and then getting lucky and participating in a contest with lots of math problems.
Hello mango_lassi,
Thank you so much for your comment !
What do you mean by solving "purely algorithmic problems" ?
Do you recommend some problem sets (which contains hard-easy problems (like CF DIV 2 C-D/DIV 1 A-B) to practice implementation/speedsolving easy problems ?)
Also I know these:
Random graph algos (DFS/BFS/Djastra/Kruskal/Prim, something about Dilworth though idk anything about max cut/min cut/centroid decomposition or any other algo etc. However I have solved ~60% problems from http://artofproblemsolving.com/community/c6h601134p5359256 Chapte 8 (on Graph theory) )
Basic greedy techniques/divide and conquer/DP techniques
Basic Data Structures (BST, Union Find, Segment Tree, Linked List though I don't have much practice with them and I don't know anything else).
Which things should I learn to reach high orange/low red or USACO mid plat ? Note that I'm preferring being able to solve around 2 problems in USACO platinum consistently more than my rating on CF (though both would be better !). Please don't give lots of topics since I can't practice all of them thoroughly in such short time.
Thank you so much for all your help !
Don't focus so much on learning specific algorithms. If you have a strong background you can learn new ones pretty quickly anyway.
Instead, just practice on problems.
Yeah, you can learn everything you need just by solving lots of problems. The best difficulty range is probably div1A-C. There you can see problems from most topics, and they're easy enough that they're likely solvable even if you're not familiar with that type of a problem. If you want to specifically focus on usaco, you should solve problems of similar difficulty from there, as the distribution of topics is likely different from codeforces.
Slightly offtopic but yeah, if you want to do USACO practice USACO. One notable difference between USACO and CF is that on USACO if you have a stupid naive idea, submit it anyway, because their grading is proportional to the number of test cases solved. I probably have gotten 70% of testcases by submitting random crap at some point.
Remember that the USACO Open (the final contest of the season) is in March, with three contests preceding it, so that may give you some more time to achieve your goals. And also, mid-purple seems to be enough to get to training camp.
Personally, I am pretty bad at contest math so I often find that issue hindering me in competitive programming. Given your math background, you'll do great :)
To reach cf orange solve alot of cf problems To reach usaco plat (easier of the goals) solve alot of usaco problems