ABC（AtCoder Beginner Contest）記事一覧

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過去問題

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Contest	A	B	C	D	E	F	G	H/Ex
ABC388	?UPC	Heavy Snake	Various Kagamimochi	Coming of Age Celebration	Simultaneous Kagamimochi	Dangerous Sugoroku	Simultaneous Kagamimochi 2	–
ABC387	Happy New Year 2025	9×9 Sum	Snake Numbers	Snaky Walk	Digit Sum Divisible 2	Count Arrays	Prime Circuit	–
ABC386	Full House 2	Calculator	Operate 1	Diagonal Separation	Maximize XOR	Operate K	Many MST	–
ABC385	Equally	Santa Claus 1	Illuminate Buildings	Santa Claus 2	Snowflake Tree	Visible Buildings	Counting Buildings	–
ABC384	aaaadaa	ARC Division	Perfect Standings	Repeated Sequence	Takahashi is Slime 2	Double Sum 2	Abs Sum	–
ABC383	Humidifier 1	Humidifier 2	Humidifier 3	9 Divisors	Sum of Max Matching	Diversity	Bar Cover	–
ABC382	Daily Cookie	Daily Cookie 2	Kaiten Sushi	Keep Distance	Expansion Packs	Falling Bars	Tile Distance 3	–
ABC381	11/22 String	1122 String	11/22 Substring	1122 Substring	11/22 Subsequence	1122 Subsequence	Fibonacci Product	–
ABC380	123233	Hurdle Parsing	Move Segment	Strange Mirroring	1D Bucket Tool	Exchange Game	Another Shuffle Window	–
ABC379	Cyclic	Strawberries	Sowing Stones	Home Garden	Sum of All Substrings	Buildings 2	Count Grid 3-coloring	–
ABC378	Pairing	Garbage Collection	Repeating	Count Simple Paths	Mod Sigma Problem	Add One Edge 2	Everlasting LIDS	–
ABC377	Rearranging ABC	Avoid Rook Attack	Avoid Knight Attack	Many Segments 2	Permute K times 2	Avoid Queen Attack	Edit to Match	–
ABC376	Candy Button	Hands on Ring (Easy)	Prepare Another Box	Cycle	Max × Sum	Hands on Ring (Hard)	Treasure Hunting	–
ABC375	Seats	Traveling Takahashi Problem	Spiral Rotation	ABA	3 Team Division	Road Blocked	Road Blocked 2	–
ABC374	Takahashi san 2	Unvarnished Report	Separated Lunch	Laser Marking	Sensor Optimization Dilemma 2	Shipping	Only One Product Name	–
ABC373	September	1D Keyboard	Max Ai+Bj	Hidden Weights	How to Win the Election	Knapsack with Diminishing Values	No Cross Matching	–
ABC372	delete .	3^A	Count ABC Again	Buildings	K-th Largest Connected Components	Teleporting Takahashi 2	Ax + By < C	–
ABC371	Jiro	Taro	Make Isomorphic	1D Country	I Hate Sigma Problems	Takahashi in Narrow Road	Lexicographically Smallest Permutation	–
ABC370	Raise Both Hands	Binary Alchemy	Word Ladder	Cross Explosion	Avoid K Partition	Cake Division	Divisible by 3	–
ABC369	369	Piano 3	Count Arithmetic Subarrays	Bonus EXP	Sightseeing Tour	Gather Coins	As far as possible	–
ABC368	Cut	Decrease 2 max elements	Triple Attack	Minimum Steiner Tree	Train Delay	Dividing Game	Add and Multiply Queries	–
ABC367	Shout Everyday	Cut .0	Enumerate Sequences	Pedometer	Permute K times	Rearrange Query	Sum of (XOR^K or 0)	–
ABC366	Election 2	Vertical Writing	Balls and Bag Query	Cuboid Sum Query	Manhattan Multifocal Ellipse	Maximum Composition	XOR Neighbors	–
ABC365	Leap Year	Second Best	Transportation Expenses	AtCoder Janken 3	Xor Sigma Problem	Takahashi on Grid	AtCoder Office	–
ABC364	Glutton Takahashi	Grid Walk	Minimum Glutton	K-th Nearest	Maximum Glutton	Range Connect MST	Last Major City	–
ABC363	Piling Up	Japanese Cursed Doll	Avoid K Palindrome 2	Palindromic Number	Sinking Land	Palindromic Expression	Dynamic Scheduling	–
ABC362	Buy a Pen	Right Triangle	Sum = 0	Shortest Path 3	Count Arithmetic Subsequences	Perfect Matching on a Tree	Count Substring Query	–
ABC361	Insert	Intersection of Cuboids	Make Them Narrow	Go Stone Puzzle	Tree and Hamilton Path 2	x = a^b	Go Territory	–
ABC360	A Healthy Breakfast	Vertical Reading	Move It	Ghost Ants	Random Swaps of Balls	InterSections	Suitable Edit for LIS	–
ABC359	Count Takahashi	Couples	Tile Distance 2	Avoid K Palindrome	Water Tank	Tree Degree Optimization	Sum of Tree Distance	–
ABC358	Welcome to AtCoder Land	Ticket Counter	Popcorn	Souvenirs	Alphabet Tiles	Easiest Maze	AtCoder Tour	–
ABC357	Sanitize Hands	Uppercase and Lowercase	Sierpinski carpet	88888888	Reachability in Functional Graph	Two Sequence Queries	Stair-like Grid	–
ABC356	Subsegment Reverse	Nutrients	Keys	Masked Popcount	Max/Min	Distance Component Size Query	Freestyle	–
ABC355	Who Ate the Cake?	Piano 2	Bingo 2	Intersecting Intervals	Guess the Sum	MST Query	Baseball	–
ABC354	Exponential Plant	AtCoder Janken 2	AtCoder Magics	AtCoder Wallpaper	Remove Pairs	Useless for LIS	Select Strings	–
ABC353	Buildings	AtCoder Amusement Park	Sigma Problem	Another Sigma Problem	Yet Another Sigma Problem	Tile Distance	Merchant Takahashi	–
ABC352	AtCoder Line	Typing	Standing On The Shoulders	Permutation Subsequence	Clique Connect	Estimate Order	Socks 3	–
ABC351	The bottom of the ninth	Spot the Difference	Merge the balls	Grid and Magnet	Jump Distance Sum	Double Sum	Hash on Tree	–

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ABC350	Past ABCs	Dentist Aoki	Sort	New Friends	Toward 0	Transpose	Mediator	–
ABC349	Zero Sum Game	Commencement	Airport Code	Divide Interval	Weighted Tic-Tac-Toe	Subsequence LCM	Palindrome Construction	–
ABC348	Penalty Kick	Farthest Point	Colorful Beans	Medicines on Grid	Minimize Sum of Distances	Oddly Similar	Max (Sum – Max)	–
ABC347	Divisible	Substring	Ideal Holidays	Popcount and XOR	Set Add Query	Non-overlapping Squares	Grid Coloring 2	–
ABC346	Adjacent Product	Piano	Σ	Gomamayo Sequence	Paint	SSttrriinngg in StringString	Alone	–
ABC345	Leftrightarrow	Integer Division Returns	One Time Swap	Tiling	Colorful Subsequence	Many Lamps	Sugoroku 5	–
ABC344	Spoiler	Delimiter	A+B+C	String Bags	Insert or Erase	Earn to Advance	Points and Comparison	–
ABC343	Wrong Answer	Adjacency Matrix	343	Diversity of Scores	7x7x7	Second Largest Query	Compress Strings	–
ABC342	Yay!	Which is ahead?	Many Replacement	Square Pair	Last Train	Black Jack	Retroactive Range Chmax	–
ABC341	Print 341	Foreign Exchange	Takahashi Gets Lost	Only one of two	Alternating String	Breakdown	Highest Ratio	–
ABC340	Arithmetic Progression	Append	Divide and Divide	Super Takahashi Bros.	Mancala 2	S = 1	Leaf Color	–
ABC339	TLD	Langton’s Takahashi	Perfect Bus	Synchronized Players	Smooth Subsequence	Product Equality	Smaller Sum	–
ABC338	Capitalized?	Frequency	Leftover Recipes	Island Tour	Chords	Negative Traveling Salesman	evall	–
ABC337	Scoreboard	Extended ABC	Lining Up 2	Cheating Gomoku Narabe	Bad Juice	Usual Color Ball Problems	Tree Inversion	–
ABC336	Long Loong	CTZ	Even Digits	Pyramid	Digit Sum Divisible	Rotation Puzzle	16 Integers	–
ABC335	202<s>3</s>	Tetrahedral Number	Loong Tracking	Loong and Takahashi	Non-Decreasing Colorful Path	Hop Sugoroku	Discrete Logarithm Problems	–
ABC334	Christmas Present	Christmas Trees	Socks 2	Reindeer and Sleigh	Christmas Color Grid 1	Christmas Present 2	Christmas Color Grid 2	–
ABC333	Three Threes	Pentagon	Repunit Trio	Erase Leaves	Takahashi Quest	Bomb Game 2	Nearest Fraction	–
ABC332	Online Shopping	Glass and Mug	T-shirts	Swapping Puzzle	Lucky bag	Random Update Query	Not Too Many Balls	–
ABC331	Tomorrow	Buy One Carton of Milk	Sum of Numbers Greater Than Me	Tile Pattern	Set Meal	Palindrome Query	Palindrome Query	–
ABC330	Counting Passes	Minimize Abs 1	Minimize Abs 2	Counting Ls	Mex and Update	Minimize Bounding Square	Inversion Squared	–
ABC329	Spread	Next	Count xxx	Election Quick Report	Stamp	Colored Ball	Delivery on Tree	–
ABC328	Not Too Hard	11/11	Consecutive	Take ABC	Modulo MST	Good Set Query	Cut and Reorder	–
ABC327	ab	A^A	Number Place	Good Tuple Problem	Maximize Rating	Apples	Many Good Tuple Problems	–
ABC326	2UP3DOWN	326-like Numbers	Peak	ABC Puzzle	Revenge of “The Salary of AtCoder Inc.”	Robot Rotation	Unlock Achievement	–
ABC325	Takahashi san	World Meeting	Sensors	Printing Machine	Our clients, please wait a moment	Sensor Optimization Dilemma	offence	–
ABC324	Same	3-smooth Numbers	Error Correction	Square Permutation	Joint Two Strings	Beautiful Path	Generate Arrays	–
ABC323	Weak Beats	Round-Robin Tournament	World Tour Finals	Merge Slimes	Playlist	Push and Carry	Inversion of Tree	–
ABC322	First ABC 2	Prefix and Suffix	Festival	Polyomino	Product Development	Vacation Query	Two Kinds of Base	–
ABC321	321-like Checker	Cutoff	321-like Searcher	Set Menu	Complete Binary Tree	(subset sum = K) with Add and Erase	Electric Circuit	–
ABC320	Leyland Number	Longest Palindrome	Slot Strategy 2 (Easy)	Relative Position	Somen Nagashi	Fuel Round Trip	Slot Strategy 2 (Hard)	–
ABC319	Legendary Players	Measure	False Hope	Minimum Width	Bus Stops	Fighter Takahashi	Counting Shortest Paths	–
ABC318	Full Moon	Overlapping sheets	Blue Spring	General Weighted Max Matching	Sandwiches	Octopus	Typical Path Problem	Count Strong Test Cases
ABC317	Potions	MissingNo.	Remembering the Days	President	Avoid Eye Contact	Nim	Rearranging	Walk
ABC316 （欠番）	–	–	–	–	–	–	–	–
ABC315	tcdr	The Middle Day	Flavors	Magical Cookies	Prerequisites	Shortcuts	Ai + Bj + Ck = X (1 <= i, j, k <= N)	Typical Convolution Problem
ABC314	3.14	Roulette	Rotate Colored Subsequence	LOWER	Roulettes	A Certain Game	Amulets	Disk and Segments
ABC313	To Be Saikyo	Who is Saikyo?	Approximate Equalization 2	Odd or Even	Duplicate	Flip Machines	Redistribution of Piles	Group Photo
ABC312	Chord	TaK Code	Invisible Hand	Count Bracket Sequences	Tangency of Cuboids	Cans and Openers	Avoid Straight Line	snukesnuke
ABC311	First ABC	Vacation Together	Find it!	Grid Ice Floor	Defect-free Squares	Yet Another Grid Task	One More Grid Task	Many Illumination Plans
ABC310	Order Something Else	Strictly Superior	Reversible	Peaceful Teams	NAND repeatedly	Make 10 Again	Takahashi And Pass-The-Ball Game	Negative Cost
ABC309	Nine	Rotate	Medicine	Add One Edge	Family and Insurance	Box in Box	Ban Permutation	Simple Path Counting Problem
ABC308	New Scheme	Default Price	Standings	Snuke Maze	MEX	Vouchers	Minimum Xor Pair Query	Make Q
ABC307	Weekly Records	racecar	Ideal Sheet	Mismatched Parentheses	Distinct Adjacent	Virus 2	Approximate Equalization	Marquee
ABC306	Echo	Base 2	Centers	Poisonous Full-Course	Best Performances	Merge Sets	Return to 1	Balance Scale
ABC305	Water Station	ABCDEFG	Snuke the Cookie Picker	Sleep Log	Art Gallery on Graph	Dungeon Explore	Banned Substrings	Shojin
ABC304	First Player	Subscribers	Virus	A Piece of Cake	Good Graph	Shift Table	Max of Medians	Constrained Topological Sort
ABC303	Similar String	Discord	Dash	Shift vs. CapsLock	A Gift From the Stars	Damage over Time	Bags Game	Constrained Tree Degree
ABC302	Attack	Find snuke	Almost Equal	Impartial Gift	Isolation	Merge Set	Sort from 1 to 4	Ball Collector
ABC301	Overall Winner	Fill the Gaps	AtCoder Cards	Bitmask	Pac-Takahashi	Anti-DDoS	Worst Picture	Difference of Distance

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ABC300	N-choice question	Same Map in the RPG World	Cross	AABCC	Dice Product 3	More Holidays	P-smooth number	Fibonacci: Revisited
ABC299	Treasure Chest	Trick Taking	Dango	Find by Query	Nearest Black Vertex	Square Subsequence	Minimum Permutation	Dice Sum Infinity
ABC298	Job Interview	Coloring Matrix	Cards Query Problem	Writing a Numeral	Unfair Sugoroku	Rook Score	Strawberry War	Sum of Min of Length
ABC297	Double Click	chess960	PC on the Table	Count Subtractions	Kth Takoyaki Set	Minimum Bounding Box 2	Constrained Nim 2	Diff Adjacent
ABC296	Alternately	Chessboard	Gap Existence	M<=ab	Transition Game	Simultaneous Swap	Polygon and Points	Unite
ABC295	Probably English	Bombs	Socks	Three Days Ago	Kth Number	substr = S	Minimum Reachable City	E or m
ABC294	Filter	ASCII Art	Merge Sequences	Bank	2xN Grid	Sugar Water 2	Distance Queries on a Tree	K-Coloring
ABC293	Swap Odd and Even	Call the ID Number	Make Takahashi Happy	Tying Rope	Geometric Progression	Zero or One	Triple Index	Optimal Path Decomposition
ABC292	CAPS LOCK	Yellow and Red Card	Four Variables	Unicyclic Components	Transitivity	Regular Triangle Inside a Rectangle	Count Strictly Increasing Sequences	Rating Estimator
ABC291	camel Case	Trimmed Mean	LRUD Instructions 2	Flip Cards	Find Permutation	Teleporter and Closed off	OR Sum	Balanced Tree
ABC290	Contest Result	Qual B	Max MEX	Marking	Make it Palindrome	Maximum Diameter	Edge Elimination	Bow Meow Optimization
ABC289	flip	レ	Coverage	Step Up Robot	Swap Places	Teleporter Takahashi	Shopping in AtCoder store	Trio
ABC288	Many A+B Problems	Qualification Contest	Don’t be cycle	Range Add Query	Wish List	Integer Division	3^N Minesweeper	A Nameless Counting Problem
ABC287	Majority	Postal Card	Path Graph?	Match or Not	Karuta	Components	Balance Update Query	Directed Graph and Query
ABC286	Range Swap	Cat	Rotate and Palindrome	Money in Hand	Souvenir	Guess The Number 2	Unique Walk	Don’t Swim
ABC285	Edge Checker 2	Longest Uncommon Prefix	abc285_brutmhyhiizp	Change Usernames	Work or Rest	Substring of Sorted String	Tatami	Avoid Square Number
ABC284	Sequence of Strings	Multi Test Cases	Count Connected Components	Happy New Year 2023	Count Simple Paths	ABCBAC	Only Once	Count Unlabeled Graphs
ABC283	Power	First Query Problem	Cash Register	Scope	Don’t Isolate Elements	Permutation Distance	Partial Xor Enumeration	Popcount Sum
ABC282	Generalized ABC	Let’s Get a Perfect Score	String Delimiter	Make Bipartite 2	Choose Two and Eat One	Union of Two Sets	Similar Permutation	Min + Sum
ABC281	Count Down	Sandwich Number	Circular Playlist	Max Multiple	Least Elements	Xor Minimization	Farthest City	Alchemy
ABC280	Pawn on a Grid	Inverse Prefix Sum	Extra Character	Factorial and Multiple	Critical Hit	Pay or Receive	Do Use Hexagon Grid 2	Substring Sort
ABC279	wwwvvvvvv	LOOKUP	RANDOM	Freefall	Cheating Amidakuji	BOX	At Most 2 Colors	Sum of Prod of Min
ABC278	Shift	Misjudge the Time	FF	All Assign Point Add	Grid Filling	Shiritori	Generalized Subtraction Game	make 1
ABC277	^{-1}	Playing Cards Validation	Ladder Takahashi	Takahashi’s Solitaire	Crystal Switches	Sorting a Matrix	Random Walk to Millionaire	Constrained Sums
ABC276	Rightmost	Adjacency List	Previous Permutation	Divide by 2 or 3	Round Trip	Double Chance	Count Sequences	Construct a Matrix
ABC275	Find Takahashi	ABC-DEF	Counting Squares	Yet Another Recursive Function	Sugoroku 4	Erase Subarrays	Erase Subarrays	Infinite Knapsack
ABC274	Batting Average	Line Sensor	Ameba	Robot Arms 2	Booster	Fishing	Security Camera 3	XOR Sum of Arrays
ABC273	A Recursive Function	Broken Rounding	(K+1)-th Largest Number	LRUD Instructions	Notebook	Hammer 2	Row Column Sums 2	Inv(0,1)ving Insert(1,0)n
ABC272	Integer Sum	Everyone is Friends	Max Even	Root M Leaper	Add and Mex	Two Strings	Yet Another mod M	Flipping Coins 2
ABC271	484558	Maintain Multiple Sequences	Manga	Flip and Adjust	Subsequence Path	XOR on Grid Path	Access Counter	General General
ABC270	1-2-4 Test	Hammer	Simple path	Stones	Apple Baskets on Circle	Transportation	Sequence in mod P	add 1
ABC269	Anyway Takahashi	Rectangle Detection	Submask	Do use hexagon grid	Last Rook	Numbered Checker	Reversible Cards 2	Antichain

分野別の過去問題（ページトップに戻る）

bit全探索
- ABC002 D問題（派閥）
順列全探索
- ABC054 C問題（One-stroke Path）
二分探索
- ABC077 C問題（Snuke Festival）
累積和（いもす法含む）
再帰関数の応用
- ABC015 C問題（高橋くんのバグ探し）
DP（動的計画法）
グラフの問題
UnionFind
- ABC049 D問題（連結）
- ABC097 D問題（Equals）
セグメント木
- ABC185 F問題（Range Xor Query）
- ABC190 F問題（Shift and Inversions）
整数の問題
その他
- ABC最初の問題
  ABC001 A問題（積雪深差）
- 文字列圧縮
  ABC019 B問題（高橋くんと文字列圧縮）
- 組み合わせの個数
  ABC034 C問題（経路）
- 座標圧縮
  ABC036 C問題（座圧）
- $O(N^3)$ を制約を使い $O(N^2)$ にする。
  ABC051 B問題（Sum of Three Integers）
- 単純に部分文字列を全探索するとTLEする。
  ABC097 C問題（K-th Substring）