Graph Theory _ Question

What we can see on the forum is put first and done slowly.

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1062 * expensive offer enumeration Level Limit + limit stra1087 * a plug for Unix 2 point match 1094 sorting it all out Floyd or topology 1112 * team them up! 2 graph coloring + dp1122 FDNY to the rescue! Maximum short circuit 1125 stockbroker grapevine floyd1128 frame stacking topological sorting 1135 domino effect maximum short circuit 1149 * pigs network stream 1161 * Wils floyd1192 optimal connectivity subset 1201 intervals differential constraint 1236 * network of schools strong Unicom 1251 jungle roads mst1258 agri-net mst1270 following orders topological sorting 1273 drainage ditches maximum stream 1274 the perfect stall 2 points matching 1275 * cashier employee difference constraint 1287 networking mst1300 door man Euler road 1324 holedox moving bfs1325 Machine Schedule 2 points Configuration (minimum point coverage) 1364 King differential constraint 1386 play on words Euler road 1422 air raid 2 point matching 1459 Power Network Flow 1466 girls and boys 2 minute chart (Maximum Independent Group) 1469 courses 2-point match 1502 MPI maelstrom floyd1511 * invitation cards shortest 1556 The Doors shortest 1562 oil deposits dfs1603 risk shortest 1613 cave Raider shortest 1637 * sightseeing tour hybrid Diagram- network stream 1659 frogs 'neighborhood Havel-Hakimi theorem 1679 the unique MST uniqueness 1716 integer intervals difference constraint 1724 * roads Shortest-split point 175 1 highways mst1780 * Code Euler Loop 1789 truck history mst1797 Heavy Transportation min Spanning Tree 1847 tram Min-short 1861 network mst1904 * king's quest strong Unicom 1949 chores Min-short 1979 red and black dfs2031 Building a space station mst2060 taxi cab scheme 2 minute match 2075 tangled in cables Minimum Spanning Tree 2112 optimal milking network flow 2125 destroying the graph minimum cut 2135 farm tour fee flow 2139 Six Degrees of cowvin bacon floyd2226 muddy fields 2-point match 2230 watchcow Euler Loop 2239 Selecting Courses 2 point match 2240 arbitrage Shortest Path 2253 Frogger Shortest Path 2263 heavy cargo Shortest Path 2267 * from dusk till dawn or: vladimir the vampire shortest circuit 2289 Jamie's contact groups network flow 2337 catenyms Euler path 2349 Arctic network Minimum Spanning Tree 2367 genealogical tree topological sorting 2387 til the cows come home shortest circuit 2391 * ombrophobic bovines maximum stream 2394 checking an alibi shortest 2396 * Budget Network Flow 2421 * constructing roads Minimum Spanning Tree 2446 chessboard 2 point match 2455 se Cret milking machine network stream 2457 part acquisition Shortest Path 2472 106 miles to Chicago Shortest Path 2485 highways Minimum Spanning Tree 2513 colored sticks Euler road 2516 minimum cost fee stream 2536 gopher II 2 point match 2553 * bottom of a graph strong Unicom 2570 fiber network shortest 2584 T-shirt gumbo network stream 2585 window pains topological sorting 2594 * treasure matching 2 points matching 2607 firestation shortest circuit 2723 get Luffy out 2-sat2724 Purifying Machine 2-Point Matching 2728 desert King optimal proportion Spanning Tree 2749 * building Ro ADS 2-sat2762 going from u to V or from V to u? China Unicom 2935 basic wall maze bfs2942 knights of the Round Table point dual-Connected Component + bipartite graph judgment 2949 * word rings difference constraint 2983 is the information reliable? Difference constraint 2987 firing minimum cut (the solution is correct ??) 3020 antenna placement 2 point match 3026 Borg maze mst3041 asteroids 2 point match 3072 * robot Shortest Path 3159 steady cow assignment difference constraint 3160 Father Christmas flymouse strong Unicom 3164 command network minimum tree limit 3169 layout difference Constraint 3177 redundant paths dual-Unicom component 3189 steady cow assignment network stream 3204 Ikki's story I-road reconstruction maximum stream 3207 Ikki's Story IV-panda's trick 2sat3216 Repairing Company 2 minute match 3228 gold transportation network flow 3255 roadblocks shortest 3259 wormholes shortest circuit 3268 silver cow party shortest circuit 3275 ranking the cows floyd3281 dining maximum flow 3308 paratroopers minimum cut 3310 birth HIE with the pie floyd3328 cliff climbing shortest circuit 3343 road construction bridge 3439 server relocation shortest 3463 sightseeing shortest 3469 dual core CPU min cut 3487 the stable marriage problem stable marriage 3522 slim span min Spanning Tree 3594 escort of dr. who how shortest 3615 cow hurdles shortest 362 1 sightseeing cows binary enumeration + negative ring 3648 wedding 2-sat3653 Here We Go (relians) again shortest 3659 * minimum cell phone network control set 3660 cow contest topological sorting 3662 * telephone lines shortest 3678 Katu puzzle 2-sat3683 * priest John's busiest day 2-Sat solution 3687 labeling bils differential constraint or topological sorting 3692 kindergarten 2-Point Matching 3694 network undirected graph shrinkage point poj 2449 remmarguts 'date (moderate) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 2449 meaning: Classic problem: K short circuit solution: Dijkstra + A * (REC), a lot of related methods: http://acm.pku.edu.cn/JudgeOnline/showcontest? Contest_id = 1144 this question is also put in the search recommendation questions poj 3013-big Christmas tree (basic) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 3013 question: the simplest and most short circuit, but this question is too much, need better program speed and, but also pay attention to the accuracy of the solution: dijkstrapoj 3463-Sightseeing (medium) http://acm.pku.edu.cn/JudgeOnline/problem? The number of paths between the shortest path and the shortest path is greater than that of the shortest path. Do you need to really understand dijkstrapoj 3463-cow relays (hard) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 3613 question: Find the shortest solution after n edge: Floyd + multiply, greedy poj 3621-Sightseeing cows (medium) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 3621 meaning: Find a loop, happy value/total path maximum solution: parameter search + the most short circuit (MS original Bellman TLE, only through spfa) poj 3635-Full tank? (Medium) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 3635 question: the most short circuit deformation solution: wide search related: Drawing 1639-Picnic planning (difficult) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 1639 question: Minimum build tree solution with restricted vertices: greedy + prim/kruskalpoj 1679-the unique MST (basic) http://acm.pku.edu.cn/JudgeOnline/problem? The only solution to determining whether MST is: prim on the line, but still error-prone question poj 1679-desert King (medium) http://acm.pku.edu.cn/JudgeOnline/problem? What is the so-called optimal Ratio Spanning Tree solution: parameter search + primpoj 2728-Command Network (hard) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 3164 question: minimum tree graph solution: Liu Zhu algorithm. Is it less likely to be obtained? Poj 3522-slim span (basic) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 3522 question: Find a spanning tree and let the maximum and minimum edge difference between the two sides solve the problem: Kruskal uses connectivity, degree, and Topology problems, which mainly involve DFS, poj 1236-network of schools (basic) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 1236 question: how many sides can be added into a fully connected graph solution: scale down, view the degree of poj 1659-frogs 'neighborhood (basic) http://acm.pku.edu.cn/JudgeOnline/problem? Graph solution based on degree sequence: greedy, detailed proof see Havel theorem poj 1659-the bottom of a graph (basic) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 2553poj 2186-popular cows (basic) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 2186 question: poj 2762-going from u to V or from V to u? (Medium) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 2762 question: one-way connected graph determination solution: shrink point + dp find the longest chain poj 2914-minimum cut (difficult) http://acm.pku.edu.cn/JudgeOnline/problem? Graph least cut: stoer-Wagner algorithm, with network flow plus enumeration determination will be hanging poj 2914-Knights of the Round Table (difficult) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 2942 question: Check whether the dual-connected component (or block) contains the odd ring solution: Find the dual-connected component and then perform black and white dyeing to determine the relationship between the two points graph: http://hi.baidu.com/zfy0701/blog/item/57ada7ed104ce9d2b31cb104.htmlPOJ 3177-redundant paths (medium) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 3177poj 3352-road construction (medium) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 3352 question: how many sides can be added to a bidirectional connected graph solution: We recommend that you compare the scaled points of different parts separated by the cut edge to 1236, how many edges are added to a directed graph into a strongly connected graph poj 3249-Test for job (basic) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 3249 solution: BFS/DFS + dppoj 3592-instantaneous transference (basic) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 3592 solution: shrink point, the longest path, less people do water problems, pay attention to the details of poj 3687-labeling BALS (medium) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 3687 solution: topological sorting poj 3694-Network (medium) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 3694 solution: Dual-Connected Component + and query set 2-SAT problems this problem is not difficult to understand the meaning of the Union formula poj 2723-Get Luffy out (medium) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 2723poj 2749-building roads (hard) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 2749 solution: Binary + 2-Sat determination poj 3207-Ikki's Story IV-panda's trick (basic) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 3207 solution: simple 2-Sat, but other methods are faster poj 3648-wedding (medium) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 3648 solution: using 2-SAT will be more interesting, but the brute force search still 0 mspoj 3678-Katu puzzle (basic) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 3678 solution: simply validate the poj 3683-priest John's busiest day (medium) http://acm.pku.edu.cn/JudgeOnline/problem by using the Union diagram? Id = 3683 solution: the compatibility diagram between N ^ 2 enumeration points, solving the maximum flow problem of 2-Sat, there are many variants, what is the key of the max flow theorem of least cut? Is poj 1149-drainage ditches (basic) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 1273 Max inbound door poj 1459-Power Network (basic) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 1459 basic diagram poj 1637-Sightseeing Tour (crazy) http://acm.pku.edu.cn/JudgeOnline/problem? Is there a solution for the Euler's trace of a hybrid graph: undirected edges, arbitrary orientation, composition, details of the Black Book p324poj 1637-friendship (medium) http://acm.pku.edu.cn/JudgeOnline/problem? Http://hi.baidu.com/zfy0701/blog/item/a521f230b06dea9fa9018e0e.htmlPOJ 1815-cable TV network (medium) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 1966 question: how many points are removed to make the graph unconnected solution: Determine any source point, and calculate the vertex cut set by enumerative sink points (convert to edge cut ), find the smallest vertex cut poj 2112-optimal milking (basic) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 2112 binary enumeration, maximum stream poj 2391-ombrophobic bovines (medium) http://acm.pku.edu.cn/JudgeOnline/problem? Http://hi.baidu.com/zfy0701/blog/item/3e0006c4f73f0eaf8226acff.htmlPOJ 2391-budget (medium) http://acm.pku.edu.cn/JudgeOnline/problem? Question: Is there a source sink of the upstream and downstream feasible stream solution: With a matrix-Network Flow Model diagram, and then split edge related: Listen 2396-secret milking machine (basic) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 2455 binary enumeration, in general, the need to write the edge capacity update operation instead of every time all the re-map poj 2699-the maximum number of strong kings (difficult) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 2699 solution: enumerative Number of people + maximum flow (thanks to the xpcnq_71 big cow graph creation Tips) poj 2987-firing (hard) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 2987 meaning: Maximum right closure solution: first side right amplification, the first question total-maximum flow, the second question to find the minimum cut related: http://wywcgs.spaces.live.com/blog/cns! 4d861a02a3382142! 1109. Entry? & _ C02_owner = 1 profit (medium) http://www.vijos.cn/Problem_Show.asp? Id = 1352 max weight closure graph Special Case zoj 2071-technology trader is also of this type, lazy did not do http://acm.zju.edu.cn/show_problem.php? PID = 2071poj 3084-panic room (medium, good question) http://acm.pku.edu.cn/JudgeOnline/problem? According to the minimum cut modeling poj 3084-hard life (very challenging) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 3155 question: maximum density subgraph method: parameter search + maximum weight closure diagram,. v. goldberg's paper (NB solution) the application of the minimal cut model in the competition in informatics also talk about poj 3189-Steady cow assignment (medium) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 3189 question: finding the minimum range to complete the matching solution: This fully demonstrates the strength of SAP, which is purely violent. A better way is to continually Delete edges and add edges while continuing the network flow process poj 3204-Ikki's story I-road reconstruction (basic) http://acm.pku.edu.cn/JudgeOnline/problem during enumeration intervals? Id = 3204zoj 2532-Internship (basic) http://acm.zju.edu.cn/show_problem.php? PID = 2532 question: determine whether an edge is a side solution in a certain cut: DFS seeking and splitting on both sides, or brute-force enumeration (you need to write an operation to cancel an extended path (but the data is weak,) poj 3308-paratroopers (hard) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 3308poj 2125-destroying the graph (hard) http://acm.pku.edu.cn/JudgeOnline/problem? What is the minimum point weight covering poj 2125-dual core CPU (medium) http://acm.pku.edu.cn/JudgeOnline/problem? Minimum Cut poj 3469-March of the Penguins (medium) http://acm.pku.edu.cn/JudgeOnline/problem? Network Flow solution that satisfies the point Capacity Limit: Split point to change the point capacity to the edge capacity, enumerated points zoj 3498-unique attack (difficult) http://acm.zju.edu.cn/show_problem.php? PID = 2587 question: is the smallest cut the only solution: understand the nature of the DFS Minimum Cut Algorithm spoj 839-optimal marks (hard) limit 326-Perspective (medium) http://acm.sgu.ru/problem.php? C0 & problem = 326 the typical cost flow problem of the ing method can be solved by km. In addition, unless it is a special figure, generally, the algorithm of continuous increasing wide path is enough for poj 2175-evacuation plan (medium) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 2175 question: Determine whether a given solution is the optimal solution. A negative solution: Construct a stream based on the given plan, and then only one negative circle poj 3422-Kaka's matrix travels (medium) http://acm.pku.edu.cn/JudgeOnline/problem? Poj 3422-intervals (hard) http://acm.pku.edu.cn/JudgeOnline/problem? In discuss, spoj 3680-boxes (simple) Explain 371-two shortest (medium) http://acm.sgu.ru/problem.php? C0 & problem = 185 question: find two solutions to the shortest path that you don't want to pay: The cost flow, or the Shortest Path + the maximum flow. The correct understanding of the matching problem is very important. Here I would like to say a few more words: the most correct solution to the minimum weight matching is to use a large number-the current edge weight, instead of directly performing Edge Weight inversion (in this way, we can only process completely bipartite graphs with equal left and right vertices, that is, K (N, N) and above may still be a problem, after adding poj 1486-sorting slides (medium) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 1486 meaning: the necessary edge solution of the Bipartite Graph: need to really understand the maximum matching algorithm, see http://hi.baidu.com/kevin0602/blog/item/1d5be63b5bec9bec14cecb44.htmlPOJ 1904-King's Quest (medium, good question) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 1904 question: all possible matching edge solutions for a bipartite graph: although the matching algorithm is not used in the end, the idea of matching must be understood to convert it into a strongly connected component. Poj 2060-Taxi Cab Scheme (basic) http://acm.pku.edu.cn/JudgeOnline/problem? The minimum path overwrites the poj 2060-treasure registration (medium) http://acm.pku.edu.cn/JudgeOnline/problem?? Id = 3041poj 2226-muddy fields (basic) http://acm.pku.edu.cn/JudgeOnline/problem? The smallest point set overwrites = the largest matching poj 2226-Going Home (basic) http://acm.pku.edu.cn/JudgeOnline/problem? Min weight matching solution: Km algorithm poj 2195-supervisor, supervisee (medium) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 2400 question: Output all least weighted matching solutions: km, then backtracking solution, perspiration, the two matrices entered are actually the opposite of poj 2516-minimum cost (medium) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 2516 question: least weight match or least cost flow solution: Split point + km algorithm (only correct), cost flow (MS error may also pass) poj 3686-The Windy's (hard) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 3686 question: minimum weight matching solution: Split points. Even if you use the KM algorithm to access the water, the data is actually very weak (50*50*2500)-> 16 Ms: http://hi.baidu.com/kevin0602/blog/item/2829dc01d7143b087bec2c97.htmlSPOJ 412-K-path cover (hard) limit 206. roads (hard) http://acm.sgu.ru/problem.php? C0 & problem = 206 solution: classical question, can also use spoj 412 that question optimization NP problem is generally search or DP Solution poj 1419-graph coloring (basic) http://acm.pku.edu.cn/JudgeOnline/problem? The data of the question is too weak. poj 1419-all friends (difficult) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 2989 question: a very large number of groups solution: get started with the crazy TLE, and then find the paper: finding all cliques of an undirected graph (Coen bron & joep kerboscht) zoj 1492-maximum clique (basic) http://acm.zju.edu.cn/show_problem.php? PID = 1492 question: figure of the largest group of solutions: search, if the speed is required, you can refer to the corresponding paper other can not be big class poj 1470-closest common ancestors (basic) http://acm.pku.edu.cn/JudgeOnline/problem? Question: Tarjan or rmq, and the input is disgusting poj 1470-cow Marathon (basic) http://acm.pku.edu.cn/JudgeOnline/problem? The longest path solution on the tree: dppoj 1985-distance queries (medium) http://acm.pku.edu.cn/JudgeOnline/problem? Id = 1986 question: LCA solution: Tarjan or rmq