This is a really helpful article . Has anybody counted ? Sometime you find improvement, or reduce it by redundant part.. anyway... solve solve solve ~ that it what I usually do :). On a separate note, I believe it'll nice if each topic has its list of tutorials too. As I was browsing here this problem caught my eye. Thank you so much! Finally if you would like to add some problem to the list — even though I would be glad, please do so only in case of: There is nothing, or low number of problems in the topic. Paths to the problems are corrupted, can you fix them? 7988 Flow Shop (3) //Do as they say. 8017 — Mancunian and Sonu Generate Strings (5) //[NICE][DP]//+Something: Trie/SA/SET...? I wish there were tutorials and solutions gathered for these problems :D, What do you mean by hard/weak children? The only programming contests Web 2.0 platform, AtCoder Beginner Contest 189 Announcement. http://www.spoj.com/problems/SGIFT/ (4) //BS works too, http://www.spoj.com/problems/SUMSUM/ (5) //Bit-by-Bit cnt 0/1, http://www.spoj.com/problems/AKVQLD03/ (3) //Classical fenwick — easy, http://www.spoj.com/problems/ZIGZAG2/ (6) //Very nice — FW + BS + DP, http://codeforces.com/contest/849/problem/E (7) //2D Fenwick / ST+TP [NICE], http://www.spoj.com/problems/CRAYON/ (5) //VERY NICE [2*FW — begin + end], http://www.spoj.com/problems/NITT8/ (4) //Norm. yes, exactly as you say. https://www.hackerrank.com/contests/world-codesprint-7/challenges/elastic-rope/problem, https://devskill.com/CodingProblems/ViewProblem/20 [EASY], 3378 — Swamp Things [LA] — Maximum points on line, https://www.codechef.com/problems/ALLPOLY //[NICE] Point seeing polygon, http://www.spoj.com/problems/IITKWPCL/ //Point distance, LightOJ 1018 //Minimum # of lines through all pts [VERY NICE], UVA 12830 //Biggest rectangle without points inside, http://www.spoj.com/problems/AMR12C/ //Pt closest to all other points, http://www.spoj.com/problems/CLOPPAIR/ //Closest pair of points, http://codeforces.com/problemset/problem/600/D //Circles intersection, http://www.spoj.com/problems/CERC07C/en/ //Bounding circle, LightOJ 1130 //Circle x Rectangle intersection, http://codeforces.com/problemset/problem/610/D //Lines intersections (axes parallel), http://codeforces.com/problemset/problem/681/E //Circles intersection, http://codeforces.com/problemset/problem/793/C //Intersection ans similar, Gym 100190I [2011 ACM-ICPC East Central North America (ECNA 2011)] //Segment intersection, http://codeforces.com/gym/100917/problem/K, http://www.spoj.com/problems/SICRANO/ //Point-line distance, http://codeforces.com/problemset/problem/614/C //Point-line distance, https://www.hackerrank.com/contests/booking-hackathon/challenges/nearby-attractions/problem //Pt sphr, 11265 UVA 6 //Nice one | polygon — cut/pt-check/area, 11177 UVA 6 //BS+Polygon/Circle intersection, 11008 UVA 5 //with DP → #intersected triangles, 11012 UVA 5 //Nejvzdálenější body (Manhatton 3D), http://codeforces.com/problemset/problem/682/E 6 (biggest triangle), http://codeforces.com/contest/672/problem/C 4 //easy — just think it up, http://codeforces.com/contest/667/problem/A 2 //vzorecky, http://codeforces.com/contest/793/problem/C 5 //EASY but beware of epsilons (NICE), http://codeforces.com/contest/794/problem/B 2 //Can be done with BS, http://codeforces.com/contest/814/problem/D 5 //+DP on trees (NICE — but low geom. Is there something to take into account for getting a faster solution. (N*log(N)*100 ), http://codeforces.com/contest/811/problem/E (6) //VERY NICE — DSU (easier Timofey + animals), http://codeforces.com/contest/817/problem/F (7) //10^18 + MEX ~~ NICE yet problematic, http://codeforces.com/contest/816/problem/B (3) //Or offline trick makes it easier, http://codeforces.com/contest/834/problem/D (5) //+Dynamic Programming | NICE, http://www.spoj.com/problems/SBO/ (5) //preLast→ last (-1), last→ now (+1) — VERY NICE, http://www.spoj.com/problems/GOODE/ (5) //NICE: Inversion + L-Mex, http://www.spoj.com/problems/CNTPRIME/ (3) //ST+Sieve (short range), http://www.spoj.com/problems/SEGSQRSS/ (4) //NICE {weak data} ~~ SQRT works too, http://www.spoj.com/problems/MON2012/ (5) //NICE [Online][10^9 Range], http://www.spoj.com/problems/PARSUMS/ (4) //But other approaches work too, http://www.spoj.com/problems/THRBL/ (4) //Simple SA — maximum on range <= A[a], http://www.spoj.com/problems/HORRIBLE/ (3) //Totally classical, http://www.spoj.com/problems/MULTQ3/ (4) //NICE (interesting operation), http://www.spoj.com/problems/PERMPATT/ (4) //NICE [minimum][+IDEA], http://codeforces.com/contest/869/problem/E (5) //NICE — 2D [random][XOR], http://codeforces.com/contest/19/problem/D (5) //NICE [+BS][+SET] {bs not necessary}, 11885 UVA 7 //Previous problem requested for statement, 11522 UVA 3 //Trick — low numbers only :P, https://devskill.com/CodingProblems/ViewProblem/577 (4) //[NICE][TWO POINTERS], https://www.spoj.com/problems/EVENSEMIP/ (5) //[VERY NICE][SEGMENTED], http://codeforces.com/gym/101982 H //[GOLDBACH], http://codeforces.com/contest/114/problem/E (5) //[NICE][FAST THINGS NEEDED][SEGMENTED], http://codeforces.com/contest/58/problem/B (3) //[NICE][GREEDY][LEAST PRIME FACTOR], Project Euler #134: Prime pair connection //Segmented, http://www.spoj.com/problems/TDPRIMES/ (4), http://www.spoj.com/problems/VECTAR8/ (3), http://www.spoj.com/problems/NFACTOR/ (4), http://www.spoj.com/problems/HS08PAUL/ (4) //simply generate, http://codeforces.com/contest/776/problem/B (3) //Easy — trict: PM-1/ELSE-2, http://www.spoj.com/problems/GGD/ (4) // N/lowestDiv*(lowestDiv-1), http://codeforces.com/contest/822/problem/D (4) //DP + Lowest factor, http://www.spoj.com/problems/NGIRL/ (4) //Squares — Primes + BS == Easiest, http://www.spoj.com/problems/PTRI/ (5) //Very fast sieve necessary:/, http://www.spoj.com/problems/AFS/ (3) //Sum of divisort + DP, http://www.spoj.com/problems/BSPRIME/ (4) //Very fast sieve needed, http://www.spoj.com/problems/DCEPC505/ (4) //NICE — at most 10527450, http://www.spoj.com/problems/CUBEFR/ (3) //NICE — Sieve out k^3 numbers, http://www.spoj.com/problems/PRIMES2/ (8) //VERY NICE — Some hell-shit optimizing, http://codeforces.com/contest/26/problem/A (2) //Easy — many ways to solve it, https://codeforces.com/contest/1180/problem/C (4) //[MODULO][QUEUE], https://codeforces.com/gym/102001/problem/F (4) //[NICE][GREEDY], https://codeforces.com/gym/101991/problem/D (4) //[NICE][NORMALIZE][PREFIX], https://codeforces.com/gym/102021 L //[NICE][JUST DO IT], https://codeforces.com/gym/102021 D //Try one and see, https://codeforces.com/gym/101972/problem/K (3) //[EASY][STRINGS], http://codeforces.com/gym/101962/problem/K (3) //[NICE] //Complexity, http://codeforces.com/gym/101650 A //[VERY NICE][TREAP][PROBABILITY], http://codeforces.com/gym/101650 K //[NICE] //Perhaps weak TC, https://abc084.contest.atcoder.jp/tasks/abc084_c (3) //Brute-Force, http://codeforces.com/contest/908/problem/B (2) //[EASY][NICE], http://codeforces.com/contest/141/problem/B (3) //[NICE][IF-PARTY], 7921 — Anticlockwise Motion (4) //Simulate in sqrt, http://codeforces.com/contest/129/problem/B (2) //Graph, http://codeforces.com/contest/903/problem/B (2) //[NICE], http://codeforces.com/contest/120/problem/C (1), http://codeforces.com/contest/118/problem/A (1), http://codeforces.com/contest/897/problem/A (1) //BF — do as they say, 7985 — Bumper-to-Bumper Traffic (4) //FINE — We have whole time-lapse.