Contest Archive

Browse through our past competitions, problems, and solutions!
(Disclaimer: Difficulties correspond to a rough Codeforces rating and are subjective; as such, they may not be fully accurate.)

2025

A
Blueprint Printer800
ProblemUnavailable
B2
Disguises800
ProblemUnavailable
C2
Tuned Transmissions1000
ProblemUnavailable
D2
Reciprocal Roulette1000
ProblemUnavailable
E2
Slot Machines1000
ProblemUnavailable
F2
The Cardinal Quest1400
ProblemUnavailable
G2
Security Backdoor1500
ProblemUnavailable
I2
Camera Commands1700
ProblemUnavailable
J2
Cardinal Credit Fraud1700
ProblemUnavailable
K2
Recombinant Lock1900
ProblemUnavailable
10 problems
A
Blueprint Printer800
ProblemUnavailable
B1
Disguises800
ProblemUnavailable
C1
Tuned Transmissions800
ProblemUnavailable
D1
Reciprocal Roulette800
ProblemUnavailable
E1
Slot Machines1000
ProblemUnavailable
F1
The Cardinal Quest1000
ProblemUnavailable
G1
Security Backdoor1000
ProblemUnavailable
I1
Camera Commands1200
ProblemUnavailable
J1
Cardinal Credit Fraud1300
ProblemUnavailable
K1
Recombinant Lock1200
ProblemUnavailable
10 problems
A
Polly's New Laptop800
ProblemSolution
B
Make the Grade800
ProblemSolution
C
Magical Mirror800
ProblemSolution
D
Starr Showdown!800
ProblemSolution
E
Hexadecimal Hex1000
ProblemSolution
F
Blocked Out1100
ProblemSolution
G
Recursive Dartboard1200
ProblemSolution
H1
Bitstring Birthday Game (Easy Version)1200
ProblemSolution
H2
Bitstring Birthday Game (Hard Version)1200
ProblemSolution
I1
High Rollers (Easy Version)1300
ProblemSolution
I2
High Rollers (Hard Version)1400
ProblemSolution
11 problems