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Rayan
→ Pay attention
Before contest
Educational Codeforces Round 174 (Rated for Div. 2)
20:12:07
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Difficulty:
—
combinatorics
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
1917D
Yet Another Inversions Problem
combinatorics
,
data structures
,
dp
,
implementation
,
math
,
number theory
2300
x1862
1917B
Erase First or Second Letter
brute force
,
combinatorics
,
data structures
,
dp
,
strings
1100
x24563
1916H2
Matrix Rank (Hard Version)
combinatorics
,
dp
,
math
,
matrices
,
string suffix structures
2700
x558
1916H1
Matrix Rank (Easy Version)
brute force
,
combinatorics
,
dp
,
math
,
matrices
2700
x638
1914G2
Light Bulbs (Hard Version)
combinatorics
,
data structures
,
dfs and similar
,
dp
,
graphs
,
hashing
2300
x1478
1914G1
Light Bulbs (Easy Version)
brute force
,
combinatorics
,
dfs and similar
,
dp
,
dsu
,
graphs
,
math
,
trees
2100
x1985
1912K
Kim's Quest
bitmasks
,
combinatorics
,
dp
1800
x2772
1912B
Blueprint for Seating
combinatorics
,
divide and conquer
,
math
2100
x1175
1910I
Inverse Problem
*special problem
,
combinatorics
,
dp
2700
x53
1909I
Short Permutation Problem
combinatorics
,
dp
,
fft
,
math
1900
x123
1909F2
Small Permutation Problem (Hard Version)
combinatorics
,
dp
,
math
2500
x1008
1909F1
Small Permutation Problem (Easy Version)
brute force
,
combinatorics
,
dp
,
math
2200
x1944
1907E
Good Triples
brute force
,
combinatorics
,
number theory
1600
x11301
1906J
Count BFS Graph
combinatorics
,
dp
2100
x872
1906H
Twin Friends
combinatorics
,
dp
2200
x839
1905E
One-X
combinatorics
,
dfs and similar
,
dp
,
math
,
trees
2400
x1070
1895F
Fancy Arrays
combinatorics
,
dp
,
math
,
matrices
2600
x811
1893E
Cacti Symphony
combinatorics
,
dfs and similar
,
dp
,
graphs
3500
x206
1886D
Monocarp and the Set
combinatorics
,
data structures
,
math
2100
x3705
1879D
Sum of XOR Functions
bitmasks
,
combinatorics
,
divide and conquer
,
dp
,
math
1700
x7913
1879C
Make it Alternating
combinatorics
,
dp
,
greedy
1300
x18563
1876D
Lexichromatography
combinatorics
,
dfs and similar
,
dsu
,
graphs
,
two pointers
2500
x923
1876B
Effects of Anti Pimples
combinatorics
,
number theory
,
sortings
1500
x8813
1868C
Travel Plan
combinatorics
,
dp
,
implementation
,
math
,
trees
2400
x1218
1866M
Mighty Rock Tower
brute force
,
combinatorics
,
dp
,
math
,
probabilities
2400
x842
1866H
Happy Sets
combinatorics
2100
x1703
1866B
Battling with Numbers
combinatorics
,
math
,
number theory
1400
x8075
1864G
Magic Square
combinatorics
,
constructive algorithms
,
implementation
3100
x287
1863G
Swaps
combinatorics
,
dp
,
graphs
,
math
2800
x667
1862D
Ice Cream Balls
binary search
,
combinatorics
,
constructive algorithms
,
math
1300
x17978
1861E
Non-Intersecting Subpermutations
combinatorics
,
dp
,
implementation
,
math
2300
x1801
1857G
Counting Graphs
combinatorics
,
divide and conquer
,
dsu
,
graphs
,
greedy
,
sortings
,
trees
2000
x4695
1855B
Longest Divisors Interval
brute force
,
combinatorics
,
greedy
,
math
,
number theory
900
x29478
1854C
Expected Destruction
combinatorics
,
dp
,
math
,
probabilities
2500
x1584
1850G
The Morning Star
combinatorics
,
data structures
,
geometry
,
implementation
,
math
,
sortings
1500
x13381
1848F
Vika and Wiki
binary search
,
bitmasks
,
combinatorics
,
divide and conquer
,
dp
,
math
2400
x1704
1847E
Triangle Platinum?
brute force
,
combinatorics
,
implementation
,
interactive
,
math
,
probabilities
2900
x343
1844H
Multiple of Three Cycles
combinatorics
,
data structures
,
dp
,
dsu
,
math
3400
x151
1843D
Apple Tree
combinatorics
,
dfs and similar
,
dp
,
math
,
trees
1200
x18863
1843C
Sum in Binary Tree
bitmasks
,
combinatorics
,
math
,
trees
800
x34669
1842G
Tenzing and Random Operations
combinatorics
,
dp
,
math
,
probabilities
2800
x1135
1840C
Ski Resort
combinatorics
,
math
,
two pointers
1000
x30757
1840B
Binary Cafe
bitmasks
,
combinatorics
,
math
1100
x23045
1838E
Count Supersequences
combinatorics
,
dp
,
math
2500
x1565
1837E
Playoff Fixing
combinatorics
,
trees
2200
x2280
1835E
Old Mobile
combinatorics
,
dp
,
probabilities
3500
x238
1833F
Ira and Flamenco
combinatorics
,
constructive algorithms
,
data structures
,
implementation
,
math
,
sortings
,
two pointers
1700
x7970
1832E
Combinatorics Problem
brute force
,
combinatorics
,
dp
2200
x2267
1830C
Hyperregular Bracket Strings
combinatorics
,
greedy
,
hashing
,
math
,
number theory
,
sortings
2400
x1782
1829H
Don't Blame Me
bitmasks
,
combinatorics
,
dp
,
math
1700
x8295
1827A
Counting Orders
combinatorics
,
math
,
sortings
,
two pointers
1100
x20475
1824B2
LuoTianyi and the Floating Islands (Hard Version)
combinatorics
,
dfs and similar
,
math
,
probabilities
,
trees
2300
x2831
1824B1
LuoTianyi and the Floating Islands (Easy Version)
combinatorics
,
math
,
probabilities
,
trees
1800
x4839
1823A
A-characteristic
combinatorics
,
constructive algorithms
,
math
800
x16541
1821F
Timber
combinatorics
,
dp
,
fft
,
math
2600
x790
1821A
Matching
combinatorics
,
math
800
x20236
1817C
Similar Polynomials
combinatorics
,
math
2400
x1069
1815D
XOR Counting
bitmasks
,
combinatorics
,
dp
,
math
2600
x1235
1811G2
Vlad and the Nice Paths (hard version)
binary search
,
combinatorics
,
data structures
,
dp
,
math
,
two pointers
2200
x1874
1811G1
Vlad and the Nice Paths (easy version)
combinatorics
,
dp
,
math
2100
x2198
1810H
Last Number
combinatorics
,
math
2900
x147
1809G
Prediction
combinatorics
,
dp
,
math
2800
x461
1808E3
Minibuses on Venus (hard version)
brute force
,
combinatorics
,
dp
,
math
2800
x461
1808E2
Minibuses on Venus (medium version)
combinatorics
,
divide and conquer
,
dp
,
matrices
2500
x720
1808E1
Minibuses on Venus (easy version)
combinatorics
,
divide and conquer
,
dp
2200
x1400
1806D
DSU Master
combinatorics
,
dp
,
dsu
,
math
2500
x965
1799G
Count Voting
combinatorics
,
dp
,
math
2600
x827
1795D
Triangle Coloring
combinatorics
,
math
1600
x9858
1794D
Counting Factorizations
combinatorics
,
divide and conquer
,
dp
,
math
,
number theory
1900
x3722
1792F2
Graph Coloring (hard version)
brute force
,
combinatorics
,
divide and conquer
,
dp
,
fft
,
graphs
2900
x415
1792F1
Graph Coloring (easy version)
combinatorics
,
dp
,
graphs
2700
x768
1789C
Serval and Toxel's Arrays
combinatorics
,
dp
,
implementation
,
math
1500
x8958
1788D
Moving Dots
binary search
,
brute force
,
combinatorics
,
math
,
two pointers
2000
x4062
1787D
Game on Axis
combinatorics
,
dfs and similar
,
dsu
,
graphs
,
implementation
1900
x3492
1784E
Infinite Game
brute force
,
combinatorics
,
dp
,
games
,
probabilities
3100
x358
1784D
Wooden Spoon
combinatorics
,
dp
2400
x1067
1781F
Bracket Insertion
combinatorics
,
dp
,
math
,
trees
2700
x994
1780F
Three Chairs
bitmasks
,
brute force
,
combinatorics
,
data structures
,
dp
,
number theory
,
sortings
2300
x1605
1778D
Flexible String Revisit
combinatorics
,
dp
,
math
,
probabilities
2100
x2921
1777D
Score of a Tree
bitmasks
,
combinatorics
,
dfs and similar
,
dp
,
math
,
probabilities
,
trees
1900
x3663
1777B
Emordnilap
combinatorics
,
greedy
,
math
900
x17959
1776G
Another Wine Tasting Event
combinatorics
,
constructive algorithms
,
math
,
strings
2100
x2127
1774G
Segment Covering
brute force
,
combinatorics
,
constructive algorithms
,
data structures
,
dp
,
trees
3200
x456
1773G
Game of Questions
bitmasks
,
combinatorics
,
dp
,
fft
,
math
,
probabilities
2800
x409
1773D
Dominoes
combinatorics
,
flows
,
graph matchings
,
greedy
2600
x511
1771A
Hossam and Combinatorics
combinatorics
,
math
,
sortings
900
x23513
1770F
Koxia and Sequence
bitmasks
,
combinatorics
,
dp
,
math
,
number theory
3100
x756
1770E
Koxia and Tree
combinatorics
,
dfs and similar
,
dp
,
dsu
,
math
,
probabilities
,
trees
2400
x1417
1768E
Partial Sorting
combinatorics
,
math
,
number theory
2300
x1968
1767D
Playoff
combinatorics
,
constructive algorithms
,
dp
,
greedy
,
math
1500
x10299
1765C
Card Guessing
combinatorics
,
dp
,
probabilities
2600
x448
1764D
Doremy's Pegging Game
combinatorics
,
dp
,
math
2000
x2861
1763D
Valid Bitonic Permutations
combinatorics
,
dp
,
implementation
,
math
,
number theory
2200
x2124
1762E
Tree Sum
combinatorics
,
math
,
trees
2600
x704
1762C
Binary Strings are Fun
combinatorics
,
math
1400
x9439
1761F2
Anti-median (Hard Version)
combinatorics
,
dp
,
math
3500
x85
1761D
Carry Bit
combinatorics
,
math
2100
x2518
1758E
Tick, Tock
combinatorics
,
dfs and similar
,
dsu
,
graphs
2500
x876
1750G
Doping
combinatorics
,
dp
,
math
3300
x261
1750F
Majority
combinatorics
,
dp
,
math
,
strings
2700
x971
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