Test instructions: Given a weighted graph of n-point m-bars, the loop with the smallest average weight is calculated.Idea: Use the dichotomy method to solve, for each of the enumeration value of mid, determine the weight of each edge minus mid after the negative circle can be.#include Copyright NOTICE: This article for Bo Master original article, without Bo Master permission not reproduced. UVA 11090 going in cycle!! (Bellman-ford judgment Negative c
Description: it is the bare shortest path. However, it takes 60 s to change to an elevator, and there may be different places for the Olympics from I to j.
Question Analysis: Pay attention to this point when creating a graph. Change it during the Bellman-Ford process.
The following code is used:
#include
Ultraviolet A 11478 Halum (differential restraint system + Bellman-Ford), 11478 halumZookeeper
Given a directed graph, each edge has a weight. Each time you can select a node v and an integer d, reduce the weight of all vertices that end with v to d, and increase the weight of all edges starting with v to d, finally, make the minimum value of all edge values greater than zero and as big as possible.
Ps: There is a pitfall in the lrj book, which is not
POJ 3169 Layout (differential constraint system + Bellman-ford algorithm)
Layout
Time Limit:1000 MS
Memory Limit:65536 K
Total Submissions:7613
Accepted:3658
DescriptionLike everyone else, cows like to stand close to their friends when queuing for feed. FJ has N (2
Some cows like each other and want to be within a certain distance of each other in line. some really dislike each other and want to be separated
algorithm using the adjacent table + binary heap is as follows:
# Include
(4) Bellman-Ford Algorithm
When there is a negative weight in the figure, the shortest path may not exist, but it can still be obtained when the shortest path exists.
If the shortest path exists, the shortest path must not contain loops!
Cause: three factors are considered: positive ring, zero ring, and negative ring!
If it is a positive or zero ring, the shortest path will
It seems a little tired to understand English... A lot of farmland, some farmland are connected, it takes time to go from one farmland to another, and then some farmland has a wormhole hole that can transfer you to another farm, and the time will go backwards .. could FJ see itself while traveling to the farm...
In fact, it is to ask whether there is a point. He can return to this point before starting from this point, that is, whether there is a negative ring. after turning around, he returned
Advantages: The code is small, the complexity is not high, you can determine whether there will be negative ring.Cons: Low efficiency.The algorithm illustrates:The idea of this algorithm is very simple, first of all, it is based on the line from the beginning to connect with it to start the refresh, as long as the path to meet the refresh is smaller than the original path, then immediately update this data, is this data as a new numberAccording to At the same time this algorithm has a very impor
Source of Self Blog
http://www.yingzinanfei.com/2017/04/07/bellman-fordsuanfaheduilieyouhuaspfaqiudanyuanzuiduanlujing/
#include
Bellman-ford Algorithm for queue optimization (SPFA algorithm) #include
The algorithm is not interpreted here, only the code template is written.
Dijkstra
The realization of adjacency matrix
#include
Vector adjacency Table implementation
#include
Floyd
#include
map[i][j]=min (Map[i][j],map[i][k]+map[k][j]); This uses the Min function, which can be a little more time-consuming.
}
int main ()
{
int i,j,n,m; Reads N and m,n to represent the number of vertices, and m represents the number of bars on the edge
cin>>n>>m;
memset (map,max,sizeof (
# Include # include # include # include # include using namespace STD; const int maxnumber = 1e10; struct edgetype // edge type {int fromvertex; // edge start point int tovertex; // Edge End Point double weight; // Edge Weight}; Template class
Question analysis: the bare shortest path, but there are a lot of nodes. The adjacent matrix will be RE, and the graph will be stored in the adjacent linked list. Then BallmanFord went on.
Vomit: first, I didn't read the data and RESS all the time.
Question link:Pku3259 wormholes
I read Dijkstra and floyed in the data structure book (I have never written it myself)
However, if there is a negative weight edge, it will never
So I found a specific question to see how to write it.
It seems
// Determine whether a negative weight loop spfa algorithm # include # include # define maxn 505 # define maxm 6000 # define INF 1000000000 using namespace STD; int F, n, m, WW, M, U, V, W; int head [maxn], V [maxm], next [maxm], W [maxm]
To give you painter software users to detailed analysis to share the drawing Harrison portrait of the tutorial.
Tutorial list:
Original:
Copy:
The focus of this picture/visual center in the face,
From a point of view, to the shortest
The code is as follows:
#include #include Const int inf=1000000; using namespace std; int M,n, X,Y,DIST[105]; BOOL Flag=false; struct line{ //storage edge struct int x,y,w; } L[105]; Void input ()
High imitation code:
# Include # Include # Include # Include # Include # Include Using namespace STD;# Define n 205# Define M 2005Const int INF = 0x3f3f3f;Int V [m], U [m], d [N], W [m], E;Void addedge (int A, int B, int X ){V [e] = B;U [e] =;W [E ++
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