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Educational Codeforces Round 169 (Rated for Div. 2)
19:16:06
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Difficulty:
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combine-tags-by-or
*combine tags by OR
2-sat
binary search
bitmasks
brute force
chinese remainder theorem
combinatorics
constructive algorithms
data structures
dfs and similar
divide and conquer
dp
dsu
expression parsing
fft
flows
games
geometry
graph matchings
graphs
greedy
hashing
implementation
interactive
math
matrices
meet-in-the-middle
number theory
probabilities
schedules
shortest paths
sortings
string suffix structures
strings
ternary search
trees
two pointers
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Problems
#
Name
121B
Lucky Transformation
strings
1500
x2558
120F
Spiders
dp
,
greedy
,
trees
1400
x3556
120E
Put Knight!
games
,
math
1400
x2707
120D
Three Sons
brute force
1400
x1910
118D
Caesar's Legions
dp
1700
x17179
117A
Elevator
implementation
,
math
1300
x1989
115B
Lawnmower
greedy
,
sortings
1500
x2457
114B
PFAST Inc.
bitmasks
,
brute force
,
graphs
1500
x3585
113A
Grammar Lessons
implementation
,
strings
1600
x2279
111A
Petya and Inequiations
greedy
1400
x4712
108B
Datatypes
math
,
sortings
1400
x2438
107B
Basketball Team
combinatorics
,
dp
,
math
,
probabilities
1600
x3412
107A
Dorm Water Supply
dfs and similar
,
graphs
1400
x5034
106D
Treasure Island
brute force
,
implementation
1700
x1309
106C
Buns
dp
1700
x5875
105A
Transmigration
implementation
1700
x1826
103B
Cthulhu
dfs and similar
,
dsu
,
graphs
1500
x8699
101B
Buses
binary search
,
data structures
,
dp
1700
x2536
100I
Rotation
*special problem
,
geometry
,
math
1500
x346
100E
Lamps in a Line
*special problem
,
math
1600
x269
100D
World of Mouth
*special problem
,
strings
1500
x303
100C
A+B
*special problem
,
implementation
1400
x527
100B
Friendly Numbers
*special problem
,
implementation
1500
x541
99B
Help Chef Gerasim
implementation
,
sortings
1300
x2939
98A
Help Victoria the Wise
brute force
,
implementation
1700
x1178
96B
Lucky Numbers (easy)
binary search
,
bitmasks
,
brute force
1300
x15042
95A
Hockey
implementation
,
strings
1600
x1658
94B
Friends
graphs
,
implementation
,
math
1300
x4596
93A
Frames
implementation
1700
x1924
92B
Binary Number
greedy
1300
x4761
91B
Queue
binary search
,
data structures
1500
x6700
91A
Newspaper Headline
greedy
,
strings
1500
x3556
88B
Keyboard
implementation
1500
x4543
87A
Trains
implementation
,
math
1500
x5297
86A
Reflection
math
1600
x1362
85A
Domino
constructive algorithms
,
implementation
1300
x1775
84C
Biathlon
binary search
,
implementation
1700
x1621
83A
Magical Array
math
1300
x6175
82B
Sets
constructive algorithms
,
hashing
,
implementation
1700
x2025
81C
Average Score
greedy
,
math
,
sortings
1700
x1656
81B
Sequence Formatting
implementation
,
strings
1700
x1926
81A
Plug-in
implementation
1400
x10493
79B
Colorful Field
implementation
,
sortings
1400
x7029
77A
Heroes
brute force
,
implementation
1400
x1757
76E
Points
implementation
,
math
1700
x1694
76D
Plus and xor
dp
,
greedy
,
math
1700
x2045
75C
Modified GCD
binary search
,
number theory
1600
x12418
75B
Facetook Priority Wall
expression parsing
,
implementation
,
strings
1500
x3277
74B
Train
dp
,
games
,
greedy
1500
x1528
73A
The Elder Trolls IV: Oblivon
greedy
,
math
1600
x1327
72I
Goofy Numbers
*special problem
,
implementation
1500
x461
72H
Reverse It!
*special problem
,
implementation
1600
x264
71C
Round Table Knights
dp
,
math
,
number theory
1600
x6397
71B
Progress Bar
implementation
,
math
1300
x4464
70B
Text Messaging
expression parsing
,
greedy
,
strings
1600
x1748
70A
Cookies
math
1300
x3256
68B
Energy exchange
binary search
1600
x4317
66D
Petya and His Friends
constructive algorithms
,
math
,
number theory
1700
x3111
66A
Petya and Java
implementation
,
strings
1300
x6310
65B
Harry Potter and the History of Magic
brute force
,
greedy
,
implementation
1700
x1331
64C
Table
*special problem
,
greedy
,
implementation
,
math
1600
x335
64B
Expression
*special problem
,
expression parsing
1500
x1009
64A
Factorial
*special problem
,
implementation
1300
x2764
63C
Bulls and Cows
brute force
,
implementation
1700
x1663
62A
A Student's Dream
greedy
,
math
1300
x3418
61B
Hard Work
strings
1300
x3831
60B
Serial Time!
dfs and similar
,
dsu
1400
x4537
60A
Where Are My Flakes?
implementation
,
two pointers
1300
x3582
59C
Title
expression parsing
1600
x2060
58B
Coins
greedy
1300
x12084
57B
Martian Architecture
implementation
1600
x1004
57A
Square Earth?
dfs and similar
,
greedy
,
implementation
1300
x2855
56C
Corporation Mail
data structures
,
expression parsing
,
implementation
1700
x1141
56B
Spoilt Permutation
implementation
1300
x3685
55B
Smallest number
brute force
1600
x2805
54A
Presents
implementation
1300
x2048
53D
Physical Education
sortings
1500
x1983
53B
Blog Photo
binary search
,
implementation
1700
x1390
52B
Right Triangles
combinatorics
1600
x2015
51B
bHTML Tables Analisys
expression parsing
1700
x859
51A
Cheaterius's Problem
implementation
1300
x1801
50B
Choosing Symbol Pairs
strings
1500
x5624
49C
Disposition
constructive algorithms
,
math
1700
x1668
49B
Sum
math
1500
x2447
48D
Permutations
greedy
1500
x2467
46C
Hamsters and Tigers
two pointers
1600
x2391
45I
TCMCF+++
greedy
1400
x2358
44H
Phone Number
dp
1700
x1716
44E
Anfisa the Monkey
dp
1400
x5001
44C
Holidays
implementation
1300
x3306
44B
Cola
implementation
1500
x1946
43C
Lucky Tickets
greedy
1300
x4221
42B
Game of chess unfinished
implementation
1700
x933
42A
Guilty --- to the kitchen!
greedy
,
implementation
1400
x2813
41C
Email address
expression parsing
,
implementation
1300
x3712
41B
Martian Dollar
brute force
1400
x3949
40B
Repaintings
math
1600
x1141
40A
Find Color
constructive algorithms
,
geometry
,
implementation
,
math
1300
x3962
39J
Spelling Check
hashing
,
implementation
,
strings
1500
x2909
39H
Multiplication Table
implementation
1300
x2680
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