Topic Link: Click to open the linkTest instructionsGiven a direction graph, ask:1) Select at least a few vertices. Ability to proceed from these vertices to reach all vertices2) At least how many edges to add. Talent makes it possible to reach all vertices from whatever vertexNumber of vertices After the strong connected component is obtained, the shrinkage point is calculated, and the degree of each point's penetration is computed.The answer to the f
(Subtask B). One extension means introducing one new member into the list of receivers of one school.InputThe first line contains a integer n:the number of schools in the network (2 OutputYour program should write, lines to the standard output. The first line should contain one positive integer:the solution of subtask A. The second line should contain the solution of subtask B.Sample Input52 4 3 04 5 0001 0Sample Output12The following resolution turn
the number of paths = number of points at the end of the path = total number of points-number of non-end points = Total number of points-two of the number of matches in the graph, so let's do a binary match.As the ball number increases, the minimum number of columns required is monotonous, so it can be two points. But two points each time to re-build the maximum flow, if enumerated in sequence, each time only need to add some edge, and then continue
HDU 4888 Redraw Beautiful Drawings network flow graph, hduredraw
Question:
Given n, m, k
The following n integers a [n]
The following m integers B [n]
Use numbers [0, k] to construct a matrix of n * m
If a Unique solution exists, this matrix is output. If multiple solutions exist, Not Unique is output. If no solution exists, Impossible is output.
Idea: network s
the degree of love to the minimum is how big?Problem Solving Ideas:Each shed does not live on a cow, so it is a multiple match. Match the time of the two-point enumeration of the degree of affection of the interval size, according to the interval size to enumerate the beginning and end of the interval, and then run multiple matches to determine whether it is legal. Note that the interval size is calculated. And, uh, when the data is read in, Maps[i][j] is not the i_th cow's favorite value for j
Question:
Returns an undirected graph and calculates the number of cut points in the graph. (If vertex I and its adjacent edges are removed, the remaining graph is not connected, Then I is the cut point)
Analysis:
There is a mature DFS Algorithm for Finding cut points. One is written as a backup template.
/*
Zju1311 Netwo
the absence of a setExample: bzoj1497,bzoj2127,bzoj19342. Two points belong to the same set pay Val priceAt this time, the nature of the graph is a binary graph. (Face-beatingThen we can flip the nature of the two-part point, that is, the left point is selected, and the right point even T is selected.So after the transformation the problem became the first one. And just (I,j,val) (J,i,val)Example: bzoj1976
Topic Links:POJ1637Test instructionsA picture that gives a forward and a no-edge, asking if there is a Euler circuit that passes through all sides only onceProblem Solving Ideas:The solution of Euler circuit of mixed graph requires the use of network flow, and the concrete modeling method is as follows:1, first to all the non-directional direction, and then the statistics of all points in the degree and the
Question link: Click the open link
Question:
Given the scores of n teams, output any feasible solution.
There are only one and only one game for any two of the n teams, A and B.
The competition results are divided into four types:
1. A + 3, B + 0
2. A + 0, B + 3
3. A + 2, B + 1
4. A + 1, B + 2
We found that in each result, two teams scored and always three. In four cases, they all split and form three.
Therefore, we can combine any two teams into a single point.
Connect N points to the source po
for(inti =0; I ) About if(Visx[i]) theLx[i]-=D; the for(inti =0; i ) the { + if(Visy[i]) ly[i] + =D; - ElseSlack[i]-=D; the }Bayi } the } the intres =0; - for(inti =0; i ) - if(Linker[i]! =-1) theRes + =g[Linker[i]][i]; the returnRes; the } the - voidINI () the { thescanf"%d",n); the inti,j;94 for(i =0; I ){ the for(j =0; J ) thescanf"%d",g[i][j])
The main topic: the direction of the map to cut pointsTopic Ideas:A point u is a cut point when and only if one of the two two conditions is met:1. The point is the root node and has at least two child nodes2.u is not a root, and satisfies the presence (U,V) as a branch edge (or parent-child edge, that is, U is the father of V in the search tree), making DFN (U) Then pay attention to the read in, Easy re#include #includestring.h>#include#include#include#include#include#defineMAXSIZE 1005#defineL
Title Address: POJ 1144Cut points. There are two inferences to infer whether a point is a cut point:Suppose U is a cut point, and only if the following 1 bars are met1, assuming U is the root, then you must have more than 1 subtrees tree2, suppose you are not a root. Then (U,V) is the branch edge. When Low[v]>=dfn[u].Then according to these two sentences to find a cut point can be.The code is as follows:#include POJ 1144 Network (undirected
If Networkx is not good, pip uninstall then install1) Look at each node's social situationImport Networkx as Nxin [2]: nx.read such as Nx.read_adjlist Nx.read_dot Nx.read_ Edgelist this time should be in a series of edges and Dot folder fbdata in [3]: g = nx.read_edgelist ('0.edges') At this point G inherits the various method of read, viewing the case of G in [5]: Len (G.nodes ()), Len (G.edges ()) out[5]: (333, 2519)The 0 ego user then appears to has 333 friends (nodes), and there are 2519 con
, then you and V belong to a set } Else if(Pre[v] FA) Lowu=min (Lowu, pre[v]); } returnLowu;}intLcaintUintv) { intR =find (U); intL =Find (v); if(r = =l)returnret; if(Pre[u] >Pre[v]) Swap (U, v); while(Pre[u] Pre[v]) { if(Union (pa[v], v)) RET--; V=Pa[v]; } while(U! = V)//v after the previous while either U or the nearest public ancestor of U and v { if(Union (U, Pa[u]) ret--; U=Pa[u]; } returnret;}voidinit () {mem (Pre,0); Mem (PA,0); for(intI=0; ii
Transferred from http://blog.csdn.net/regina8023/article/details/45815023 It
's written in front .
Network flow with upper and lower bounds is limited by the flow of the edge, which must be within the range of [Down,up].
In fact, the ordinary network flow is a special network with the upper and lower bounds of the flow, but each side of the flow limit to [0,ca
graph theory algorithm-Network maximum flow template "Ek;dinic"ek TemplatesIncrease traffic by finding the minimum residue in the augmented residual network every timeconst int Inf=1e9;int n,m,s,t;struct node{int v,cap;}; vectorDinic templatesConstruct hierarchy + Block flow augmentationconst int Inf=1e9;int n,m;int s,t;int tot=1;struct node{int v,f,nxt;} E[10
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