Hi CodeForces !
Recently , I learn Graphs . and Now I want to solve Problems in CF about graphs.
So please everyone that have a collection of Graphs Problems (DFS,BFS,LCA,Dijkestra,...) Share that with me. I know this a repetitive question and a lot of people asked it in the past but please answer me. :(
a2oj has been shut down until further notice . :( and tags "dfs and similar" , "graphs" , "trees" when I sort them by solving , I see a hard problems;
so please share with me
Sorry for very very poor English :)
Good day to you,
Here is some list of Graph Problems. Yes sadly there are just a few problems in each group. If you would like to target some specific group more directly just say (sometime there are more problemsthan just in spoilers but it would need more direct search — also a can hardly do this for "general" topics like dfs, but for some I could)
11312 UVA (3)
11392 UVA (4)
http://mirror.codeforces.com/contest/653/problem/E (6)
http://mirror.codeforces.com/contest/769/problem/C 5 //FL:ODD/**** | bfs+greed NICE
10968 UVA (3) //EASY + NICE (bfs withot <=2 nodes)
http://mirror.codeforces.com/contest/796/problem/D (3) //NICE+EASY ... print visited in bfs (not par)
10888 UVA (4) //VERY NICE — but not main technique ... ++ DP /or/ MCMF
http://mirror.codeforces.com/contest/821/problem/D (5) //VERY NICE — Consider only points not GRID
http://www.spoj.com/problems/DIGOKEYS/ (4) //Easy [Nice problem — weird statement]
http://www.spoj.com/problems/SPIKES/ (3) //Easy bfs (# of 's' * 2)
http://www.spoj.com/problems/MULTII/ (4) //VERY NICE: BFS over numbers (K*10+d)%N
http://www.spoj.com/problems/ADV04F1/ (5) //VERY NICE: [imple] ~ N^4*BigConstant
http://www.spoj.com/problems/INVESORT/ (5) //Big limit (really usefull :P)
10977 UVA (3)
928 UVA (3)
13116 UVA (4)
314 UVA (3)
11487 UVA (4)
5622 LA (7)
11931 UVA (5)
http://www.spoj.com/problems/KNMOVE/ 3 //simple knights
http://www.spoj.com/problems/SERGRID/ 3 //almost classical
http://www.spoj.com/problems/NAKANJ/ 3 //Classical chess — KNIGHT
http://www.spoj.com/problems/PUCMM223/ (4) //NICE (but not many languages) — 2 moving [x][y]
http://www.spoj.com/problems/SPIRALGR/ (4) //NICE (not typical) [SIEVE]
http://www.spoj.com/problems/DCEPC706/ (4) //NICE — travelling outside
http://mirror.codeforces.com/contest/35/problem/C (3) //No obstacles [multiple starts]
http://www.spoj.com/problems/ARBITRAG/ (4) //Or Floyd-Warshall
11439 (UVA)
http://mirror.codeforces.com/contest/732/problem/F 7
http://mirror.codeforces.com/contest/700/problem/C 7
http://www.spoj.com/problems/EC_P/ (3) //bridges ONLY
http://www.spoj.com/problems/SUBMERGE/ (3) //Direct articulation
http://www.spoj.com/problems/GRAFFDEF/ (5) //Bridge tree
http://mirror.codeforces.com/contest/715/problem/C 9
http://mirror.codeforces.com/contest/741/problem/D 8
13164 UVA (7)
http://mirror.codeforces.com/contest/752/problem/F 5
http://mirror.codeforces.com/contest/766/problem/E 6
http://mirror.codeforces.com/contest/833/problem/D 7 //Very nice — hard (thinking + imple) + FW
http://www.spoj.com/problems/HOLI/ (4) //VERY NICE: 2*Distances from centroids
12186 UVA (3)
http://mirror.codeforces.com/contest/734/problem/E (5)
http://mirror.codeforces.com/contest/727/problem/A (3)
http://mirror.codeforces.com/contest/723/problem/E (6)
http://mirror.codeforces.com/contest/709/problem/E (6)
http://mirror.codeforces.com/contest/710/problem/E (4)
http://mirror.codeforces.com/contest/758/problem/E (8)
11323 UVA (5)
http://mirror.codeforces.com/contest/760/problem/B (3)
http://mirror.codeforces.com/contest/761/problem/E (6)
http://mirror.codeforces.com/contest/638/problem/B (3) //connect cons. letters
http://mirror.codeforces.com/contest/638/problem/C (4) //greedy idea — easy
http://mirror.codeforces.com/contest/638/problem/D (5) //spec-DAG articulatin
http://mirror.codeforces.com/contest/767/problem/C (4)
http://mirror.codeforces.com/contest/781/problem/C (5)
http://mirror.codeforces.com/contest/794/problem/D (5) //NICE! Right done dfs
http://mirror.codeforces.com/contest/802/problem/K (5) //Slightly DP-like (NICE) TREE
http://mirror.codeforces.com/contest/813/problem/C (3) //Simply 2 DFS: NICE + EASY
http://mirror.codeforces.com/contest/841/problem/D (4) //DFS while tracking "next"
http://mirror.codeforces.com/contest/845/problem/G (5) //Keep track of cycles
http://mirror.codeforces.com/contest/844/problem/E (5) //Post-Order → line, Connect i → N-2: star
http://www.spoj.com/problems/CAC/ (5) //VERY NICE! — Find all cycles in cactus
http://mirror.codeforces.com/contest/849/problem/C (3) //State search by gauss
http://mirror.codeforces.com/contest/846/problem/E (5) //NICE: DFS + some overflow logic
http://www.spoj.com/problems/KOZE/ (3) //NICE: Floods
http://www.spoj.com/problems/RIOI_2_3/ (4) //DFS /OR/ BFS /OR/ DSU [NICE][EASY][BF]
http://www.spoj.com/problems/MAKEMAZE/ (3) //EASY — Simple dfs on grid
http://mirror.codeforces.com/contest/861/problem/F (5) //VERY NICE: Modify dfs tree so it remains connected
http://www.spoj.com/problems/GHOSTS/ (3) //NICE — must remain dag after each QR
http://www.spoj.com/problems/AMR10J/ (5) //VERY NICE! — DFS+DP [DAG with cycles]
http://mirror.codeforces.com/contest/24/problem/A (2)//NICE [DFS-ON-CYCLE]
http://mirror.codeforces.com/contest/29/problem/C (3) //Find begining/end of line (graph)
http://mirror.codeforces.com/contest/29/problem/D (4) //Tree [implementation][simulation]
http://mirror.codeforces.com/contest/716/problem/D 7
12047 UVA 4
11514 UVA 4
http://mirror.codeforces.com/contest/757/problem/F 7
11338 UVA (4)
11374 UVA (4)
11097 UVA (4) //Divide to N*1000 nodes and go!
13172 UVA (5) //6*DJ per query + permutations
10816 UVA (4) //Easy Linear-Search by answer + DJ with path
http://mirror.codeforces.com/contest/827/problem/F 7 //Very nice — Even&Odd
http://www.spoj.com/problems/DELIVER/ (5) //Normalize coordinates + Optimalize
http://www.spoj.com/problems/CCHESS/ (4) //Dijkstra as knight
http://mirror.codeforces.com/contest/723/problem/F 7
13153 UVA (5)
13169 UVA (3)
11987 UVA (3)
11474 UVA (4)
http://mirror.codeforces.com/contest/687/problem/D 6
http://mirror.codeforces.com/contest/680/problem/E 7 //+precalculation/brute force
http://mirror.codeforces.com/contest/766/problem/D 5
http://www.spoj.com/problems/LEXSTR/ (3) //Nice na stringu
http://mirror.codeforces.com/contest/805/problem/C 3 //NICE (dijkstra like :P)
http://www.spoj.com/problems/IITKWPCI/ (3) //VERY NICE
http://www.spoj.com/problems/FRNDCIRC (3) //Classical DSU (NICE for practice)
http://www.spoj.com/problems/FOXLINGS/ (3) Easy — just renumbering
http://www.spoj.com/problems/NITTROAD/ (4) //Process from back
http://www.spoj.com/problems/SHAHBG/ (2) //DSU not needes (simulated by array)
http://mirror.codeforces.com/contest/598/problem/D (3) //Can be solved with DFS too
http://mirror.codeforces.com/contest/9/problem/E (4) //Making one big cycle
http://mirror.codeforces.com/contest/25/problem/D (4) //Could be done linear too
http://mirror.codeforces.com/contest/28/problem/B (4) //NICE [imho bad statement]
http://mirror.codeforces.com/contest/789/problem/D //Adj EG + Self/everything
http://mirror.codeforces.com/contest/21/problem/D (5) //[NICE][EulerTour+DP]
http://mirror.codeforces.com/contest/36/problem/E (6) //VERY NICE [4odd is hardest]
http://www.spoj.com/problems/FASTFLOW/en/ //Raw (no sauce)
4322 — Destroying the bus stations (Live Archive)
11380 — Down Went The Titanic (UVA) //Interesting grid problem
6395 — Surely You Congest (LA) //VERY NICE [slightly advanced]
7204 — Blood groups (LA)
http://mirror.codeforces.com/gym/100963 (Flame of Nucleus — F)
11167 — Monkeys in the Emei Mountain //Also harder (imho)
http://mirror.codeforces.com/problemset/problem/808/F (+BS)
http://mirror.codeforces.com/problemset/problem/653/D (+BS)
13000 — VIP Treatment (+BS)
1242 — Necklace
https://www.deadline24.pl/assets/problemsets/dl24.elim.2017.B.en.pdf (DEADLINE 24 problem — not sure if it can be submited :O)
3487 — Duopoly (Near matching)
http://mirror.codeforces.com/problemset/problem/847/J //Not sure if matching is right solutions but it works [also very near to matching]
http://mirror.codeforces.com/problemset/problem/727/D
http://mirror.codeforces.com/problemset/problem/704/D [Also advanced]
5418 — A Plug for UNIX (LA)
4957 — Fake scoreboard (LA) //If I remember well, other solutions was also possible
1155 — Power Transmission (LOJ) //(classical)
https://www.codechef.com/problems/ROBOTDAG //Ford-Fukherson
10804 — Gopher Strategy (UVA)
11506 — Angry Programmer (UVA) //Nodes division
10511 — Councilling (UVA)
563 — Crimewave
1306 — The K-League (UVA)
1345 — Jamie's Contact Groups
10092 — The Problem with the Problem Setter
Problem B. Roller Coaster Scheduling (GCJ — 2017)
259 — Software Allocation (UVA)
5905 — Pool construction (LA) //Imho harder
10480 — Sabotage
13211 UVA (5) //NICE — FW adding states
http://www.spoj.com/problems/ROHAAN/ (3) //Classical
http://mirror.codeforces.com/contest/25/problem/C (4) //Adding new edges .. need FW principal
http://mirror.codeforces.com/contest/33/problem/B (3) //NICE [dijkstra could work too]
http://mirror.codeforces.com/contest/27/problem/D (5)
11387 (UVA) 4
http://www.spoj.com/problems/VFRIEND2/ (5) //Graph possible check
http://mirror.codeforces.com/contest/859/problem/E (4) //VERY NICE (2 cases: CYCLE [x2] / TREE [x(Size+1)]
http://mirror.codeforces.com/contest/847/problem/C (2) //Forest making Easy&Nice
http://mirror.codeforces.com/contest/863/problem/C (3) //Cycle in states
http://www.spoj.com/problems/DSUBTREE/ (5) //Isomorphism on trees (try all subsets)
http://www.spoj.com/problems/TREEISO/ (4) //Simple isomorphism of trees
http://www.spoj.com/problems/MATCHING/ //Raw (no sauce)
6234 — Tile Cut (LA)
10080 — Gopher II (UVA) //Easy — sympathic
11419 — SAM I AM (UVA) //Grid-Matching
http://mirror.codeforces.com/gym/101485 (Elementary Math — E) //Very nice principal [not that hard]
3673 — Black-White Grid (UVA) //Grid
12927 — Points Cover (UVA)
6851 — The Programmers (LA)
6887 — Book Club //NICE
6571 — It Can Be Arranged
12530 — Game of Tiles
http://mirror.codeforces.com/gym/100820 (Airport — A) //Nice one
http://mirror.codeforces.com/gym/100753 (Bounty Hunterr II — B) //VERY NICE — I refered multiple times to this principal
http://www.spoj.com/problems/NITT4/
http://mirror.codeforces.com/gym/101408 (Cat vs Dog — C)
1171 — Knights in Chessboard (II) (LOJ) //Classical chess
11985 — Prime Independence (UVA)
http://www.spoj.com/problems/SCPC11H/ //Very nice — yet not hard
12644 — Vocabulary
http://mirror.codeforces.com/gym/101047/problem/H
http://mirror.codeforces.com/problemset/problem/659/E
12972 — Cuban Challenge (UVA)
1201 — Taxi Cab Scheme (UVA)
12963 — Astragalus Nitidiflorus
6525 — Attacking rooks (LA)
3415 — Guardian of Decency (LA)
http://www.spoj.com/problems/AMR12A/
12159 — Gun Fight (UVA)
https://www.codechef.com/problems/CHEFYODA //Imho matching is not the crucial part here
12831 — Bob the Builder
http://mirror.codeforces.com/problemset/problem/831/D
11262 — Weird Fence
12549 — Sentry Robots
11138 — Nuts and Bolts
http://www.spoj.com/problems/ADACITY/
http://www.spoj.com/problems/ADAPATH/
http://www.spoj.com/problems/ADAGROW/
http://mirror.codeforces.com/gym/100800 (Aqueduct Construction — A)
10806 — Dijkstra, Dijkstra.
12944 — Earthquake Disaster
12891 — Risk of Trading
11613 — Acme Corporation
https://www.codechef.com/problems/HOGON
http://www.spoj.com/problems/BNMT/ //Solved with MCMF yet I remember I thought normal flows would work too
http://mirror.codeforces.com/problemset/problem/818/G
http://mirror.codeforces.com/problemset/problem/802/C
http://mirror.codeforces.com/contest/863/problem/F (5) //VERY NICE
http://www.spoj.com/problems/COT/ (7) //ON TREE [but very tight TLE]
http://www.spoj.com/problems/GOT/ (5) //ON TREE
http://www.spoj.com/problems/TFRIENDS/ (4) //just scc size
http://www.spoj.com/problems/CAPCITY/ (4) //scc destination [WEAK TC]
http://mirror.codeforces.com/contest/22/problem/E (5) //[NICE][make it strongly connected][SRC>DST]
BLINNET SPOJ (3)
11183 UVA (4) //Directed [need to know algo!]
http://www.spoj.com/problems/ULM09/ (3) //Sum-Kruskal
http://www.spoj.com/problems/IITKWPCG/ (4) //VERY NICE [log instead of price]
http://mirror.codeforces.com/contest/17/problem/B (3) //Spanning tree [no dsu]
11478 UVA (5)
http://mirror.codeforces.com/contest/765/problem/E 5
http://mirror.codeforces.com/contest/770/problem/C 4 //reduce + toposort
http://mirror.codeforces.com/contest/825/problem/E 4 //Toposort from biggest/backward
http://www.spoj.com/problems/CODESPTI/ (6) //VERY NICE — Hard/Weak children
http://mirror.codeforces.com/contest/746/problem/G 5
http://mirror.codeforces.com/contest/750/problem/F 9
http://www.spoj.com/problems/RTREE/ 3 //longest path tree — query
13175 UVA (2) //something like preorder build
http://mirror.codeforces.com/contest/796/problem/C (3) //Just counting — inc by at most 2
http://mirror.codeforces.com/contest/797/problem/D (4) //VERY NICE — sort + D&C all
http://mirror.codeforces.com/contest/805/problem/E (4) //NICE — Treewidth coloring (greedy)
http://mirror.codeforces.com/contest/828/problem/D (3) //Star construction
http://www.spoj.com/problems/TREEDEGREE/ (3) //Degree from euler tree
http://www.spoj.com/problems/UCV2013J/ (3) //Find what is leaf in Binary Tree
http://www.spoj.com/problems/GCPC11J/ (3) //Finding ceter
http://mirror.codeforces.com/contest/34/problem/D (3) //Simple reconstruction + DFS
13089 — Golden Coins (UVA)
http://mirror.codeforces.com/problemset/problem/855/C
http://mirror.codeforces.com/problemset/problem/718/D
https://www.codechef.com/problems/TWOCOINS
https://www.hackerrank.com/contests/101hack35/challenges/road-maintenance/problem
7649 — Performance Review (LA)
http://mirror.codeforces.com/problemset/problem/741/D
http://mirror.codeforces.com/problemset/problem/592/D
https://www.codechef.com/problems/TOMJERGA
http://mirror.codeforces.com/problemset/problem/814/D
1220 — Party at Hali-Bula (UVA)
https://www.hackerrank.com/contests/june-world-codesprint/challenges/r-tree-decoration/problem
12452 — Plants vs. Zombies HD SP (UVA)
http://mirror.codeforces.com/problemset/problem/735/E
https://www.codechef.com/problems/COLTREE
12466 — Ancestors (UVA)
6829 — Intrepid climber (LA)
https://www.hackerrank.com/contests/101hack35/challenges/jeanies-route
12257 — The Queue (UVA)
http://www.spoj.com/problems/ADASALES/
http://mirror.codeforces.com/problemset/problem/805/F
http://mirror.codeforces.com/problemset/problem/763/D
1218 — Perfect Service
3346 — Perfect Domination on Trees (same as above -_-)
12093 — Protecting Zonk
10859 — Placing Lampposts
http://mirror.codeforces.com/problemset/problem/23/E //NICE [but requires big int]
http://mirror.codeforces.com/problemset/problem/14/D (5) //NICE [sorting-one][2DFS]
http://www.spoj.com/problems/TWOPATHS/ (6) //VERY NICE Same as above ~ bigger constraints
http://mirror.codeforces.com/contest/868/problem/E (8) //VERY NICE — HARD — on tree
10937 UVA (4) //find '!' / BFS / TSP — NICE!
10944 UVA (4)
10818 UVA (5) //Easy — but not-easy implementation: ++Dijkstra [LEX!]
http://www.spoj.com/problems/A_W_S_N/ (4) //BFS + TSP (path) — NICE
11930 UVA (4)
http://mirror.codeforces.com/contest/776/problem/D (5)
http://mirror.codeforces.com/contest/733/problem/F 7
11354 UVA (4)
http://www.spoj.com/problems/POLICEMEN/ (3) //simple + small graph
http://www.spoj.com/problems/QTREE2/ (5) //very easy if bin. understrood
http://mirror.codeforces.com/contest/828/problem/F 7 // Differently MST / Outside
http://mirror.codeforces.com/contest/832/problem/D (5) //Classical + Depth /OR/ HLD +ST
http://www.spoj.com/problems/DRTREE/ (5) //NICE [finding ancestor + depths]
http://mirror.codeforces.com/problemset/problem/838/B (6) //VERY NICE [HLD + ET + ST]
http://www.spoj.com/problems/NTICKETS/ (4) //Maximum on path
http://www.spoj.com/problems/GRASSPLA/ (5) //HLD
http://mirror.codeforces.com/contest/855/problem/D (4) //VERY VERY BAD STATEMENT (not so bad problem)
Good Luck & Have Georgeous Day
You must make a blog of problems which you collected, and I must bookmark it :D It would be great.
By the way, your problems on spoj are very nice, thanks for them.
Good day to you :)
Hmm interesting Idea :) I'll think about it
And thanx — very nice to hear ^_^
D you also have DP list, if yes. Please share, i am new here.
Good day to you,
well actually I keep a few DP problems, here they are:
http://www.spoj.com/problems/ADAZOO/
http://www.spoj.com/problems/ADASEQEN/
http://www.spoj.com/problems/ADAMOLD/
11552 UVA (3)
12172 UVA (3)
4507 LA (5)
4510 LA (5) [+ geometry]
12181 UVA (6)
http://mirror.codeforces.com/contest/729/problem/F 6
http://mirror.codeforces.com/contest/735/problem/E 9
http://mirror.codeforces.com/contest/731/problem/E 5
12030 UVA (4)
http://mirror.codeforces.com/contest/721/problem/E 7
http://mirror.codeforces.com/contest/742/problem/D 4
12040 UVA (5)
http://mirror.codeforces.com/contest/712/problem/D 5
13162 UVA (6)
http://mirror.codeforces.com/contest/743/problem/E 6
11908 UVA (3)
11932 UVA (4)
http://mirror.codeforces.com/contest/745/problem/E (7)
11806 UVA (4)
http://mirror.codeforces.com/contest/747/problem/F (5)
11843 UVA (4)
http://mirror.codeforces.com/contest/752/problem/E (5)
http://mirror.codeforces.com/contest/703/problem/E (7)
11753 UVA (4)
11725 UVA (5)
http://mirror.codeforces.com/contest/722/problem/E (9)
http://mirror.codeforces.com/contest/760/problem/F (8)
11795 UVA (3)
11654 UVA (4)
11523 UVA (5)
11404 UVA (4)
11432 UVA (4)
11451 UVA (4) //C==20 mistake in statement
11301 UVA (4)
http://mirror.codeforces.com/contest/762/problem/D 5
11361 UVA (4) //digit DP
11365 UVA (7)
11391 UVA (4) //easy+implementation
11394 UVA (3)
11218 UVA (2)
11125 UVA (4) //slightly implementation
11076 UVA (3)
11081 UVA (4) //3 string subsequences (beware of fail)
http://mirror.codeforces.com/contest/678/problem/E (5) //bitset dp + probability
http://mirror.codeforces.com/contest/766/problem/C (4)
http://mirror.codeforces.com/contest/667/problem/C (3)
http://www.spoj.com/problems/MOVIFAN/ (3)
http://www.spoj.com/problems/ORDSUM23/ (3)
http://www.spoj.com/problems/DIVSEQ/ (4) //N^3 (but better...) works fine
http://mirror.codeforces.com/contest/633/problem/F (7) //Tree dp
http://www.spoj.com/problems/ADJDUCKS/ (4) sort + pick 2-3 continous O(N)
http://www.spoj.com/problems/JLNT/ (4) //pick 0 or 2 | 1e3*5e3
http://www.spoj.com/problems/TPCPALIN/ (5) //500^3 works (3rd countable)
http://www.spoj.com/problems/COLORSEG/ (4) //50^4==OK 50^4log(N)=TLE NICE
http://www.spoj.com/problems/POWERCAR/ (3) //1e3*1e3*2 — follow rules
http://www.spoj.com/problems/INGRED/ (5) //TSP-like [reduce + go]
http://www.spoj.com/problems/BADXOR/ (4) //classical subsets
http://www.spoj.com/problems/SPCO/ (5) //64*64*2 DP {OPT: prime O(1) + clear only half}
http://www.spoj.com/problems/WAYHOME/ (5) //NICE: 1) 1*1 b)12,1,**,2
http://www.spoj.com/problems/NFURY/ (2) //Minimal sum of squares
http://www.spoj.com/problems/GDIL/ (3) //combinatorics
http://mirror.codeforces.com/contest/791/problem/D (5) //Tree
http://mirror.codeforces.com/contest/791/problem/E (6) //V,K,X — pick any
http://mirror.codeforces.com/contest/789/problem/C (3)
13176 (4) //N^6
13179 (5) //NICE [Ath][Bth][TimeDiff]
http://mirror.codeforces.com/contest/796/problem/E (6) //NICE: N*P*K*K (WC can't happen!)
http://mirror.codeforces.com/contest/797/problem/E (4) //NICE: Almost BF-able (but care of low K)
http://mirror.codeforces.com/contest/793/problem/D (3) //NICE & EASY: begin/end/actual/USED
http://mirror.codeforces.com/contest/803/problem/E (4) //State search — many IF's (EASY)
http://mirror.codeforces.com/contest/805/problem/F (7) //NICE: DP on tree + fast BF + hack
http://mirror.codeforces.com/contest/808/problem/E (5) //NICE!
http://mirror.codeforces.com/contest/811/problem/C (4) //Precalculate + DP (greedy thinking)
10817 UVA 4 //Easy but slightly implementation
10859 UVA 4 //Nice — on tree .. but for a reason small constrains
10898 UVA 4 //Hash is lesser than 1e6 .. try everything
http://mirror.codeforces.com/contest/812/problem/B (3) //Not only DP, yet imho easiest ..many spec cases
http://mirror.codeforces.com/contest/813/problem/D (5) //VERY VERY NICE — N*N (none picked between a/b)
http://mirror.codeforces.com/contest/814/problem/E 5 //VERY NICE — Harder imple: Combinatorics
http://mirror.codeforces.com/problemset/problem/816/E (6) //NICE — Tree (hard 2C complexity)
http://mirror.codeforces.com/contest/837/problem/D (5) //NICE — yet kinda pain [must be iterative]
http://www.spoj.com/problems/AUT/ (4) //NICE — K is interesting ~ at most 1600
http://www.spoj.com/problems/GNYR04C/ (3) //Easy — Nice idea [Big→ Low approach]
http://www.spoj.com/problems/TIEROPE/ (4) //Process 2*L ~ otherwise pick BIG
http://www.spoj.com/problems/IITKWPCE/ (4) //Palindromes [efficiency!] — NICE!
IITKWPCD SPOJ (4) //+Slightly geometry
http://www.spoj.com/problems/LKS/ (3) //Classical knapsack
http://www.spoj.com/problems/UOFTAE/ (3) //Easy & Sympatic DP
http://www.spoj.com/problems/DCOWS/ (4) //Very NICE (sort + GO)
http://www.spoj.com/problems/FARIDA/ (3) //Easy & Sympatic ((u+1) | Price+(u+2))
http://www.spoj.com/problems/AU7_5/ (2) //EASY: dyn(n-1)+dyn(n-k-1)
http://www.spoj.com/problems/NAIVELOK/ (4) //NICE [depalindromisation]
http://mirror.codeforces.com/contest/846/problem/C (4) //With print
http://www.spoj.com/problems/CNT_LUCK/ (4) //Number (binary) dp [NICE] {ull care 0-1}
http://www.spoj.com/problems/MAY99_4/ (3) //Almost combinatoric Sub and 0/1,1/0
http://www.spoj.com/problems/GEEKOUNT/ (4) //Number dp
http://www.spoj.com/problems/MUTDNA/ (4) // N*2 (turned?) [not sure if grd poss.]
http://www.spoj.com/problems/RIOI_3_2/ (5) //VERY NICE (easy imple — Number Theory thinking)
http://www.spoj.com/problems/MAXWOODS/ (3) //NICE [EASY][GRID]
http://www.spoj.com/problems/DIEHARD/ (3) //Easy — prolly solvable by greedy (but dp is easier)
http://www.spoj.com/problems/DCEPC810/ (4) //VERY VERY NICE — Subsequence 2pointers+2bools
http://www.spoj.com/problems/EQ2/ (4) //NICE: Digit + Carry (from back) — iff-party
http://www.spoj.com/problems/DCEPC501/ (3) //NICE & EASY
http://www.spoj.com/problems/NUMTSN/ (4) //NICE — Thinking or Opti
http://www.spoj.com/problems/GONE/ (4) //NICE & EASY [digits]
http://www.spoj.com/problems/RAONE/ (4) //NICE & EASY [digits] — almost similar as above
http://www.spoj.com/problems/STRSEQ/ (4) //VERY VERY NICE — Next-Function
http://www.spoj.com/problems/MYQ8/ (4) //VERY NICE — 3x3 tic-tac-toe [implementation]
http://mirror.codeforces.com/contest/859/problem/C (3) //Easy+Sympathic [PrefixSumOptional]
http://mirror.codeforces.com/contest/859/problem/D (4) //NICE [Probabilities]
http://www.spoj.com/problems/UNICA/ (4) //VERY NICE [Posibilities][Print][Classical]
http://www.spoj.com/problems/KOPC12H/ (4) //NICE Digit-DP
http://www.spoj.com/problems/DRACULA/ (4) //NICE Digit-DP (Both sides) — iterate by sum
http://www.spoj.com/problems/ABCPATH/ (3) //DP over dfs (maybe without dp works too?)
http://www.spoj.com/problems/BEHAPPY/ (2) //Easy one — low constraints
http://www.spoj.com/problems/STRCOUNT/ (4) //No input (over bits)
http://mirror.codeforces.com/contest/855/problem/B (2) //prolly not even necessary
http://mirror.codeforces.com/contest/855/problem/C (4) //dp on tree
http://mirror.codeforces.com/contest/855/problem/E (5) //VERY NICE — Digits & Bitmask & Query (learning!)
http://www.spoj.com/problems/PAINTWAL/ (6) //VERY NICE — Imho hard (opti could beat)
http://www.spoj.com/problems/ADFRUITS/ (3) //Very simple (substring == subsequence)
http://www.spoj.com/problems/MAIN113/ (2) //NICE but somehow too low constraints
http://www.spoj.com/problems/MAIN112/ (4) //NICE — Bitmask
http://mirror.codeforces.com/contest/864/problem/E (5) //VERY NICE — Sort
http://www.spoj.com/problems/NOVICE63/ (4) //NICE -On digits (binary)
http://www.spoj.com/problems/TUG/ (3) //NICE + Observation {N>100 == YES}
http://www.spoj.com/problems/DOMINO1/ (4) //Used map to solve it
http://www.spoj.com/problems/NY10E/ (2) //Easy dp
http://www.spoj.com/problems/MAIN72/ (3) //Easy knapsack
http://www.spoj.com/problems/NOVICE43/ (2) //Unbelievably low constraints
http://mirror.codeforces.com/contest/598/problem/E (4) //N^5 strategy works fine [VERY NICE]
http://www.spoj.com/problems/CHAIR/ (3) //Maybe combinatorics too?
http://www.spoj.com/problems/ACPC10D/ (3) //NICE — DAG traversal
http://www.spoj.com/problems/CPCRC1C/ (4) //Digits dp (return pair)
http://www.spoj.com/problems/BORW/ (3) //Inc+Dec sequence (small array)
http://mirror.codeforces.com/problemset/problem/16/E (5) //Bitmask [NICE]
http://mirror.codeforces.com/problemset/problem/18/E (5) //VERY NICE {no need for second iteration}
http://mirror.codeforces.com/contest/2/problem/B (5) //NICE — 2/5 are in-fact independent
http://mirror.codeforces.com/contest/4/problem/D (3) //Classical [FW works too] XY > xy
http://mirror.codeforces.com/contest/6/problem/D (4) //NICE (N^4)
http://mirror.codeforces.com/contest/321/problem/E (7) //VERY NICE — D&C Trick
http://mirror.codeforces.com/contest/868/problem/F (8) //VERY VERY NICE D&C Trick — With MO Principal
http://mirror.codeforces.com/contest/8/problem/C (5) //NICE — Masks [N*2^N]
http://mirror.codeforces.com/contest/868/problem/E (8) //VERY NICE — HARD — on tree
http://mirror.codeforces.com/contest/10/problem/D (4) //LCIS [NICE]
http://mirror.codeforces.com/contest/13/problem/C (5) //NICE [sorting][only elements from array]
http://mirror.codeforces.com/contest/17/problem/C (5) //[NICE][iterative-sparse][+idea]
http://mirror.codeforces.com/contest/19/problem/B (4) //Knapsack (after good look)
http://mirror.codeforces.com/contest/30/problem/C (4) //Probabilities + (slight)GEO
http://mirror.codeforces.com/contest/31/problem/E (4) //[NICE]
http://mirror.codeforces.com/contest/41/problem/D (4) //With printing
http://www.spoj.com/problems/ADASALES/
13089 — Golden Coins (UVA)
http://mirror.codeforces.com/problemset/problem/855/C
http://mirror.codeforces.com/problemset/problem/718/D
https://www.codechef.com/problems/TWOCOINS
https://www.hackerrank.com/contests/101hack35/challenges/road-maintenance/problem
7649 — Performance Review (LA)
http://mirror.codeforces.com/problemset/problem/741/D
http://mirror.codeforces.com/problemset/problem/592/D
https://www.codechef.com/problems/TOMJERGA
http://mirror.codeforces.com/problemset/problem/814/D
1220 — Party at Hali-Bula (UVA)
https://www.hackerrank.com/contests/june-world-codesprint/challenges/r-tree-decoration/problem
12452 — Plants vs. Zombies HD SP (UVA)
http://mirror.codeforces.com/problemset/problem/735/E
https://www.codechef.com/problems/COLTREE
12466 — Ancestors (UVA)
6829 — Intrepid climber (LA)
https://www.hackerrank.com/contests/101hack35/challenges/jeanies-route
12257 — The Queue (UVA)
http://mirror.codeforces.com/problemset/problem/805/F
http://mirror.codeforces.com/problemset/problem/763/D
1218 — Perfect Service
3346 — Perfect Domination on Trees (same as above -_-)
12093 — Protecting Zonk
10859 — Placing Lampposts
http://mirror.codeforces.com/problemset/problem/23/E //NICE [but requires big int]
http://mirror.codeforces.com/problemset/problem/14/D (5) //NICE [sorting-one][2DFS]
http://www.spoj.com/problems/TWOPATHS/ (6) //VERY NICE Same as above ~ bigger constraints
http://mirror.codeforces.com/contest/868/problem/E (8) //VERY NICE — HARD — on tree
Good Luck & Have Nice Day ^_^
Good morning sir. Thank you for the problems! :)
DONE
Much helpfull
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Topological Sort: 510C - Fox And Names
brdy throwback
CSES Problem Set Really Cool Problems
Handbook
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