[英]How can I represent edges for a graph in terms of a list?
我们如何将图表表示为边缘列表?
There's three common ways of doing this: 这有三种常见的方法:
Adjacency matrix: AV * V table of edge weights, where the ith column on the jth row is the weight of the edge between vertices i and j. 邻接矩阵:边缘权重的AV * V表,其中第j行的第i列是顶点i和j之间的边的权重。 If there is no edge, infinity is often used (or you can use some sentinel value, like -1).
如果没有边缘,则经常使用无穷大(或者您可以使用一些标记值,如-1)。
Adjacency lists: An array of V linked lists. 邻接列表:V链表的数组。 Each ith list in the array is a list of edges leaving the ith vertice.
数组中的每个第i个列表是离开第i个顶点的边列表。
Edge list: Simply a list of tuples (u, v) of edges. 边缘列表:只是边缘元组(u,v)的列表。
Different ones are suitable for different purposes. 不同的适用于不同的目的。 Personally I find the adjacency lists to be the most useful, but if you have a very dense graph then an adjacency matrix can improvement performance and memory usage.
我个人认为邻接列表是最有用的,但如果你有一个非常密集的图形,那么邻接矩阵可以改善性能和内存使用。
If you wanna store exactly edges, use matrix of weights: int** M;
如果你想准确存储边缘,使用权重矩阵:
int** M;
, where M[i][t]
is the length of the edge between i and t vertices. 其中
M[i][t]
是i和t顶点之间的边长。
If your graph edges have weight of 1, you could store graph in adjacency matrix, where M[i][t]
equals to: 如果图形边缘的权重为1,则可以将图形存储在邻接矩阵中,其中
M[i][t]
等于:
If you requre structure, critical for memory usage, store your graph in the linked list, where each vertex has structure: 如果您需要对内存使用至关重要的结构,请将图表存储在链表中,每个顶点都有结构:
struct Vertex
{
int N;
Vertex* next;
};
So you would have array of Vertex structures, each containing pointer to the next it is connected to. 因此,您将拥有Vertex结构数组,每个结构都包含指向它所连接的下一个结构的指针。 For example, here is some linked-list-graph:
例如,这是一些链表图:
Unless you really want to implement the representation yourself, as a learning exercise or to have more control, consider using a library such as igraph which is a C library for representing and manipulating graphs. 除非你真的想自己实现表示,作为学习练习或者有更多控制,否则考虑使用诸如igraph之类的库来表示和操作图形。 Or go one abstraction level down - build adjacency lists or edge lists yourself, but use the list-building capabilities of glib rather than rolling your own.
或者降低一个抽象级别 - 自己构建邻接列表或边缘列表,但使用glib的列表构建功能而不是自己编译。
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.