Problemset - Codeforces

→ Pay attention

Before contest
Codeforces Round (Div. 2)
5 days
Register now »

*has extra registration

→ Filter Problems

Difficulty: —

combinatorics

Add tag

Problems

#	Name
1983E	I Love Balls combinatorics, math, probabilities	2300	x2618
1982E	Number of k-good subarrays bitmasks, brute force, combinatorics, divide and conquer, dp, math, meet-in-the-middle	2300	x1974
1979C	Earning on Bets binary search, combinatorics, constructive algorithms, number theory	1200	x22696
1976E	Splittable Permutations combinatorics, data structures, dfs and similar, greedy, math, trees	2500	x1374
1976D	Invertible Bracket Sequences binary search, combinatorics, data structures, divide and conquer, implementation, two pointers	2000	x6023
1975F	Set bitmasks, brute force, combinatorics, dfs and similar, divide and conquer, dp, math	2600	x1096
1974C	Beautiful Triple Pairs combinatorics, data structures	1400	x19678
1967E2	Again Counting Arrays (Hard Version) combinatorics, dp, math	3500	x242
1967E1	Again Counting Arrays (Easy Version) combinatorics, dp, fft, math	3100	x485
1967C	Fenwick Tree bitmasks, brute force, combinatorics, data structures, dp, math, trees	2300	x2339
1958F	Narrow Paths *special problem, combinatorics	2000	x268
1957E	Carousel of Combinations brute force, combinatorics, dp, math, number theory	2400	x1705
1957C	How Does the Rook Move? combinatorics, dp, math	1600	x12349
1954F	Unique Strings combinatorics, dp, math	3100	x482
1954D	Colored Balls combinatorics, dp, math, sortings	1800	x8561
1952E	Sweep Line *special problem, combinatorics, games, math		x349
1951G	Clacking Balls combinatorics, math, probabilities	3100	x564
1948F	Rare Coins combinatorics, math, probabilities	2500	x1769
1946E	Girl Permutation combinatorics, dp, math, number theory	2200	x3345
1943D2	Counting Is Fun (Hard Version) combinatorics, dp	2800	x1246
1943D1	Counting Is Fun (Easy Version) brute force, combinatorics, dp, math	2400	x2058
1942G	Bessie and Cards combinatorics, dp, math	2800	x880
1942E	Farm Game combinatorics, games	2300	x2060
1935D	Exam in MAC binary search, combinatorics, implementation, math	1800	x11372
1933G	Turtle Magic: Royal Turtle Shell Pattern bitmasks, brute force, combinatorics, constructive algorithms, dfs and similar, math	2300	x1234
1931G	One-Dimensional Puzzle combinatorics, math, number theory	2000	x3891
1931F	Chat Screenshots combinatorics, dfs and similar, graphs	1700	x13089
1931D	Divisible Pairs combinatorics, math, number theory	1300	x34376
1930I	Counting Is Fun combinatorics	3500	x116
1930E	2..3...4.... Wonderful! Wonderful! combinatorics, dp, math	2400	x1547
1929F	Sasha and the Wedding Binary Search Tree brute force, combinatorics, data structures, dfs and similar, math, trees	2300	x2405
1929D	Sasha and a Walk in the City combinatorics, dp, math, trees	1900	x6012
1928F	Digital Patterns combinatorics, data structures, implementation, math	2900	x516
1925D	Good Trip combinatorics, dp, math, probabilities	1900	x5118
1924E	Paper Cutting Again combinatorics, probabilities	3100	x656
1924D	Balanced Subsequences combinatorics, dp, math	2700	x1578
1922B	Forming Triangles combinatorics, constructive algorithms, math, sortings	1200	x23913
1920E	Counting Binary Strings combinatorics, dp, math	2100	x3581
1919E	Counting Prefixes combinatorics, constructive algorithms, dp, implementation, math	2600	x1198
1917D	Yet Another Inversions Problem combinatorics, data structures, dp, implementation, math, number theory	2300	x2146
1917B	Erase First or Second Letter brute force, combinatorics, data structures, dp, strings	1100	x41051
1916H2	Matrix Rank (Hard Version) combinatorics, dp, math, matrices, string suffix structures	2700	x690
1916H1	Matrix Rank (Easy Version) brute force, combinatorics, dp, math, matrices	2700	x757
1914G2	Light Bulbs (Hard Version) combinatorics, data structures, dfs and similar, dp, graphs, hashing	2300	x1935
1914G1	Light Bulbs (Easy Version) brute force, combinatorics, dfs and similar, dp, dsu, graphs, math, trees	2100	x2514
1912K	Kim's Quest bitmasks, combinatorics, dp	1800	x4714
1912B	Blueprint for Seating combinatorics, divide and conquer, math	2100	x1504
1910I	Inverse Problem *special problem, combinatorics, dp	2700	x70
1909I	Short Permutation Problem combinatorics, dp, fft, math	1900	x185
1909F2	Small Permutation Problem (Hard Version) combinatorics, dp, math	2500	x1310
1909F1	Small Permutation Problem (Easy Version) brute force, combinatorics, dp, math	2200	x2361
1907E	Good Triples brute force, combinatorics, number theory	1600	x17395
1906J	Count BFS Graph combinatorics, dp	2100	x1175
1906H	Twin Friends combinatorics, dp	2200	x1173
1905E	One-X combinatorics, dfs and similar, dp, math, trees	2400	x1356
1895F	Fancy Arrays combinatorics, dp, math, matrices	2600	x1137
1893E	Cacti Symphony combinatorics, dfs and similar, dp, graphs	3500	x390
1886D	Monocarp and the Set combinatorics, data structures, math	2100	x4308
1879D	Sum of XOR Functions bitmasks, combinatorics, divide and conquer, dp, math	1700	x11479
1879C	Make it Alternating combinatorics, dp, greedy	1300	x30204
1876D	Lexichromatography combinatorics, dfs and similar, dsu, graphs, two pointers	2500	x1113
1876B	Effects of Anti Pimples combinatorics, number theory, sortings	1500	x10393
1868C	Travel Plan combinatorics, dp, implementation, math, trees	2400	x1418
1866M	Mighty Rock Tower brute force, combinatorics, dp, math, probabilities	2400	x1027
1866H	Happy Sets combinatorics	2100	x1976
1866B	Battling with Numbers combinatorics, math, number theory	1400	x9569
1864G	Magic Square combinatorics, constructive algorithms, implementation	3100	x405
1863G	Swaps combinatorics, dp, graphs, math	2800	x1081
1862D	Ice Cream Balls binary search, combinatorics, constructive algorithms, math	1300	x20466
1861E	Non-Intersecting Subpermutations combinatorics, dp, implementation, math	2300	x2133
1857G	Counting Graphs combinatorics, divide and conquer, dsu, graphs, greedy, sortings, trees	2000	x5796
1855B	Longest Divisors Interval brute force, combinatorics, greedy, math, number theory	900	x51016
1854C	Expected Destruction combinatorics, dp, math, probabilities	2500	x2019
1850G	The Morning Star combinatorics, data structures, geometry, implementation, math, sortings	1500	x16042
1848F	Vika and Wiki binary search, bitmasks, combinatorics, divide and conquer, dp, math	2400	x2209
1847E	Triangle Platinum? brute force, combinatorics, implementation, interactive, math, probabilities	2900	x440
1844H	Multiple of Three Cycles combinatorics, data structures, dp, dsu, math	3400	x317
1843D	Apple Tree combinatorics, dfs and similar, dp, math, trees	1200	x22835
1843C	Sum in Binary Tree bitmasks, combinatorics, math, trees	800	x40936
1842G	Tenzing and Random Operations combinatorics, dp, math, probabilities	2800	x1831
1840C	Ski Resort combinatorics, math, two pointers	1000	x54156
1840B	Binary Cafe bitmasks, combinatorics, math	1100	x25202
1838E	Count Supersequences combinatorics, dp, math	2500	x1973
1837E	Playoff Fixing combinatorics, trees	2200	x2605
1835E	Old Mobile combinatorics, dp, probabilities	3500	x359
1833F	Ira and Flamenco combinatorics, constructive algorithms, data structures, implementation, math, sortings, two pointers	1700	x10900
1832E	Combinatorics Problem brute force, combinatorics, dp	2200	x2676
1830C	Hyperregular Bracket Strings combinatorics, greedy, hashing, math, number theory, sortings	2400	x2405
1829H	Don't Blame Me bitmasks, combinatorics, dp, math	1700	x11698
1827A	Counting Orders combinatorics, math, sortings, two pointers	1100	x32016
1824B2	LuoTianyi and the Floating Islands (Hard Version) combinatorics, dfs and similar, math, probabilities, trees	2300	x3676
1824B1	LuoTianyi and the Floating Islands (Easy Version) combinatorics, math, probabilities, trees	1800	x6515
1823A	A-characteristic combinatorics, constructive algorithms, math	800	x17396
1821F	Timber combinatorics, dp, fft, math	2600	x1040
1821A	Matching combinatorics, math	800	x21527
1817C	Similar Polynomials combinatorics, math	2400	x1268
1815D	XOR Counting bitmasks, combinatorics, dp, math	2600	x1574
1811G2	Vlad and the Nice Paths (hard version) binary search, combinatorics, data structures, dp, math, two pointers	2200	x2248
1811G1	Vlad and the Nice Paths (easy version) combinatorics, dp, math	2100	x2647
1810H	Last Number combinatorics, math	2900	x177

The only programming contests Web 2.0 platform

Server time: Oct/19/2026 20:01:43 (g2).

Desktop version, switch to mobile version.

Supported by