Kattis

Solutions to Kattis competitive programming exercises, mainly in Python 3.

I also write detailed solution pages for particularly interesting exercises that I solve (see list with links in below section).

Many of the non-trivial exercises have a NOTES comment in source file with thought process/reasoning/observations.

Email me with any comments or questions.

General notation

I try to keep same variable names as used in the Kattis problem statement, unless they are really confusing.

Otherwise I try to stick to the following notation when solving exercises:

Click to expand general notation for variables

s : a string
c : a single character
d : a dictionary/hashmap
res : whatever the final result is
inps : if inputs require some kind of processing
curr,prev,best : when doing some kind of updating of current vs. previous vs. overall best values
cnt : when counting something
seen : when storing some kind of lookup of previously seen values, visited nodes in a graph, etc.
flg : a flag boolean for exiting loops or tracking if conditions are met
t,T,tc,TC : testcases
q,Q : queries
x,xs : generic names for moving through an iterable
r,c,R,C,dr,dc : current row/column, number of rows/columns in a grid, change in row/column
moves : allowed moves in some kind of grid or maze, e.g. [(-1,0), (0,1)]
board,grid : state of some kind of input maze/game board/grid configuration
acc : accumulator/range sum
dp : dynamic programming array
goods,bads : for combinatorics exercises when counting good/bad objects or states
stk : a stack
q,pq : queue, priority queue of some kind
ss,mm,hh : when working with dates and times
hi,lo,mid : when binary searching
PRECOMPUTE,LOOKUP,REF : in exercises with multiple queries of a precomputed answer

Exercises with detailed solution pages

Exercises which I found particularly interesting for some reason, and decided to write-up a solution page:

• Lucky Draw - kattis: luckydraw
• Swap Space - kattis: swapspace
• Sequential Manufacturing - kattis: sequentialmanufacturing
• Exits in Excess - kattis: exitsinexcess
• Please, Go First - kattis: pleasegofirst
• Farey Sums - kattis: fareysums
• Lopsided Lineup - kattis: lopsidedlineup
• Distance - kattis: distance
• Factorial Power - kattis: factorialpower
• Burizon Fort - kattis: burizonfort
• Johnny Applesack - kattis: applesack
• Accounting a.k.a. Bokforing - kattis: bokforing
• Jumping Yoshi - kattis: jumpingyoshi
• Ada Loveslaces - kattis: adaloveslaces
• Digit Division - kattis: digitdivision
• Integer Estate Agent - kattis: estate
• The Paladin - kattis: thepaladin
• Srednji - kattis: srednji
• Left and Right - kattis: leftandright
• Dams in Distress - kattis: damsindistress
• Sums - kattis: consecutivesums
• Divisible Subsequences - kattis: divisible
• Joyless Game - kattis: joylessgame
• Powers and Modulus - kattis: powers
• Clock Construction - Kattis: clockconstruction
• Divisibility Shortcut - Kattis: shortcut
• Eko - Kattis: eko
• The Sound of Silence - Kattis: sound
• Escape from Enemy Territory - Kattis: enemyterritory
• Happy and Unhappy Numbers - Kattis: happyandunhappynumbers
• Alehouse - Kattis: alehouse
• Razbibriga - Kattis: razbibriga
• Common Factors - Kattis: commonfactors
• ICPC Team Selection - Kattis: icpcteamselection
• Boiling Vegetables - Kattis: vegetables
• Spiderman - Kattis: spiderman
• Wolf - Kattis: wolf
• Tram - Kattis: tram
• Envious Exponents - Kattis: enviousexponents
• Canvas Line - Kattis: canvasline
• Kratki - Kattis: kratki
• Logland - Kattis: logland
• Low Power - Kattis: low
• Stop Counting! - Kattis: stopcounting
• Chemist's Vows - Kattis: chemistsvows
• Research Productivity Index - Kattis: researchproductivityindex
• Combination Lock - Kattis: combinationlock
• Financial Planning - Kattis: financialplanning
• Svada - Kattis: svada
• Orderly Class - Kattis: orderlyclass
• ETA - Kattis: eta
• Delft Distance - Kattis: delftdistance
• Irrational Division - Kattis: irrationaldivision
• Pianino - Kattis: pianino
• Reservoir - Kattis: reservoir
• LCM Pair Sum - Kattis: lcmpairsum
• Eidam-Sand Lair - Kattis: eidamsandlair
• Andrew the Ant - Kattis: andrewant
• Cake - Kattis: cake
• Frogger - Kattis: frogger

Current list of exercises to write-up

• Ocean Monument
• Brick Wall (redo the dynamic programming approach)