| Week | Problem | Points | Solution |
|---|---|---|---|
| C++ intro | Basic data types | 100 | types |
| C++ intro | BFS | 100 | standard BFS |
| C++ intro | Build the sum | 100 | naive |
| C++ intro | DFS | 100 | standard DFS |
| C++ intro | Hello World | 100 | naive |
| C++ intro | Maps | 100 | maps |
| C++ intro | Sets | 100 | sets |
| C++ intro | Sort | 100 | std::sort() |
| C++ intro | Strings | 100 | strings |
| C++ intro | Vectors | 100 | vectors |
| 1 | Build the sum | 100 | naive linear |
| 1 | Dominoes | 100 | naive linear |
| 1 | Even Pairs | 100 | Partial sums, binomial coefficient |
| 1 | Even Matrices | 100 | dimension reduction & partial sums |
| PotW 2 (2018 & 2019) | Deck of Cards | 100 | sliding window |
| 2 | Beach Bars | 100 | partial sums, sliding window |
| 2 | Burning Coins | 100 | DP, 2 tables |
| 2 | Search Snippets | 100 | ordering words by occurences, sliding window |
| 2 | The Great Game | 100 | recursion & memoization, 2 tables |
| PotW 3 (2018) | Magician and the Coin | 100 | recursion & memoization |
| PotW 3 (2019) | From Russia with Love | 100 | recursion & memoization |
| 3 | Hit | 100 | intersection |
| 3 | First hit | 100 | intersection, shuffle input and clip ray to avoid costly intersections |
| 3 | Antenna | 100 | Min_circle |
| 3 | Almost antenna | 100 | Min_circle, support points |
| PotW 4 (2018) | Defensive Line | 100 | sliding window & DP |
| PotW 4 (2019) | Chariot Race | 100 | recursion and memoization, passing information if current node is covered by parent |
| 4 | Ant Challenge | 100 | Kruskal per species, then Dijkstra |
| 4 | Buddy Selection | 100 | perfect matching |
| 4 | Building a Graph | 100 | Kurskal, Dijkstra |
| 4 | Important Bridges BGL | 100 | biconnected components |
| 4 | Shortest Paths | 100 | Dijkstra |
| PotW 5 (2018) | Hiking Maps | 100 | inclusion test & sliding window |
| PotW 5 (2019) | Motorcycles | 100 | sorting by increasing slope and then linear pass to test for intersections |
| 5 | Boats | 100 | greedy, version of earliest deadline first |
| 5 | Attack of the Clones | 100 | greedy, earliest deadline first in a circle |
| 5 | Ligth at the Museum | 100 | split & list, brute force all switch configurations |
| 5 | Punch | 100 | dynamic programming, 2D table for beverages x liters |
| 5 | High School Teams | 100 | split & list, brute force all combinations with at most k refs, for those brute force all team combinations |
| 5 (2019) | Octopussy | 100 | greedy with recursive dependency resolution |
| 5 (2019) | Planks | 100 | Split & List with to bits per plank |
| PotW 6 (2018 & 2019) | Planet Express | 100 | strong components & Dijkstra |
| 6 | Coin Tossing | 100 | max flow, making sure claimed scores and flow match number of games |
| 6 | Shopping Trip | 100 | max flow, adding edges between junctions in both directions |
| 6 | Kingdom Defence | 100 | max flow with edge demand (min capacity) |
| 6 | Tetris | 100 | max flow with splitting nodes into in- and out-nodes (vertex capacity) |
| 6 (2019) | London | 100 | max flow, edges between front/back letter combinations |
| PotW 7 (2018) | Octopussy | 100 | greedy with recursive dependency resolution |
| PotW 7 (2019) | Attack of the Clones | 100 | greedy, earliest deadline first in a circle |
| 7 | What is the Maximum | 100 | quadratic programming |
| 7 | Diet | 100 | linear programming |
| 7 | Portfolios | 100 | quadratic programming, minimize over variance matrix |
| 7 | Inball | 100 | linear programming, find closest point to every halfspace border and check |
| 7 | Radiation | 100 | LP, for every d try to find coefficiants for a 3D-polynomial of degree d that solves the constraints |
| PotW 8 (2018) | London | 100 | max flow, edges between front/back letter combinations |
| PotW 8 (2019) | Cantonal Courier | 100 | max flow |
| 8 | Graypes | 100 | Delaunay triangulation, taking shortest edge |
| 8 | Bistro | 100 | voronoi using Delaunay triangulation |
| 8 | H1N1 | 100 | Delaunay/voronoi duality and precomputing largest escape path |
| 8 | Germs | 100 | Delaunay for nearest neighbour graph |
| PotW 9 (2018 & 2019) | Suez | 100 | find constraints/objective and solve with LP |
| 9 | Satellites | 100 | max cardinality matching in bipartite graph & König algorithm |
| 9 | Algocoön | 100 | max flow / min cut with multiple min cuts |
| 9 | Real Estate Market | 100 | min cost matching |
| 9 | Canteen | 100 | min cost max flow, days as nodes and edges between days as fridge |
| 9 | Marathon | 100 | multiple max flow min cost & binary search to find the optimal flow |
| PotW 10 (2018 & 2019) | GoldenEye | 100 | voronoi (using Delaunay) & union find |
| 10 | New Tiles | --- | Cancer to implement |
| 10 | On Her Majesty's Secret Service | 100 | minimum bottleneck matching, minimizing longest edge in bipartite graph |
| 10 | Light the Stage | 100 | Delaunay for nearest neighbour & trying out all possible collisions |
| 10 | Evolution | 100 | binary search on each interval found by DFS |
| 10 | Return of the Jedi | 100 | finding 2nd most optimal spanning tree using Prim & DFS |
| 10 | Poker Chips | 100 | recursion with insane 5D memoization table |
| 10 (2019) | Defensive Line | 100 | sliding window & DP |
| 10 (2019) | Moving Books | 100 | greedy, in every round everyone picks the heaviest box he can |
| PotW 11 (2018 & 2019) | India | 100 | min cost max flow, binary search on number of suitcases to find maximum that still respects budget (see Marathon) |
| 11 | The Empire Strikes Back | 100 | Delaunay for finding max radius per shot, then LP for solving for required energy |
| 11 (2018) | Planks | 100 | Split & List with to bits per plank |
| 11 | Carsharing | 100 | min cost max flow with a space-time graph and clever edge weights |
| 11 | San Francisco | 100 | binary search over recursive function to find smallest k to achieve x points |
| 11 (2019) | DHL | 100 | DP making use of the nature of the cost function |
| 11 (2019) | Evolution | 100 | binary search on each interval found by DFS |
| 11 (2019) | Surveillance Photographs | 100 | max flow on graph with two layers |
| PotW 12 (2018) | New York | 100 | DFS over all trees, for every node discovered update node m hops above |
| PotW 12 (2019) | San Francisco | 100 | binary search over recursive function to find smallest k to achieve x points |
| 12 | Ligh Pattern | 100 | DP with linear table and two numbers per entry for normal and inverted lights |
| 12 | Casino Royale | 100 | min cost max flow, space-time graph (see Carsharing) |
| 12 | Radiation | 100 | LP, for every d try to find coefficiants for a 3D-polynomial of degree d that solves the constraints |
| 12 | Hong Kong | 100 | Delaunay/voronoi duality and precomputing max clearance for every triangle (see H1N1) |
| 12 (2019) | Clues | 100 | computing graph 2-coloring and connected components simultaneously using Delaunay triangulation |
| 12 (2019) | Magician and the Coin | 100 | recursion & memoization |
| 12 (2019) | Asterix and the tour of Gaul | 100 | min cost max flow |
| 12 (2019) | Asterix and the Roman Lines | 100 | LP |
| PotW 13 (2018) | World Cup (mock exam) | 100 | Delaunay to find relevant contour lines & LP to maximize profit under constraints |
| PotW 13 (2019) | Revenge of the Sith | 100 | Delaunay and union find to find the largest suitable set of connected planets |
| 13 | Bob's Burden | 100 | Dijkstra for finding shortest path between 3 vertices & modelling node weight with in- and out-nodes |
| 13 | Corbusier | 100 | simple DP with 2D table |
| 13 | Cantonal Courier | 100 | max flow |
| 13 | Clues | 100 | computing graph 2-coloring and connected components simultaneously using Delaunay triangulation |
| 13 | Moving Books | 100 | greedy, in every round everyone picks the heaviest box he can |
| 13 (2019) | World Cup (mock exam) | 100 | Delaunay to find relevant contour lines & LP to maximize profit under constraints |
| 13 (2019) | New York | 100 | DFS over all trees, for every node discovered update node m hops above |
| 13 (2019) | Phantom Menace | 100 | max flow for finding maximal vertex-disjoint paths |
| PotW 14 (2018) | Fleetrace | 100 | minimum cost bipartite matching |
| PotW 14 (2019) | Carsharing | 100 | min cost max flow with a space-time graph and clever edge weights |
-- may OK-Jesus be with you!