There are so many structures that can be represented with graphs, and many problems can be solved with the help of graphs. Friendships on Friendster network can be represented by a graph: vertex-verteksnya is Friendster users and no edge between A and B if and only if A is friends with B. The development of algorithms to handle the graph will have a major impact for computer science.
A graph structure can be developed by giving weight to each edge. Weighted graph can be used to represent many different concepts. For example, if a graph represents a road network so its weight can mean a long road and the highest speed limit on certain roads. Another extension on the graph is to make edgenya trending, which is technically called a digraph or a digraph (directed graph). Digraph with weighted edges is called a network.
Networks are widely used in the practical branch of graph theory network analysis. It should be noted that the network analysis, the definition of the word "network" can be different, and often means a simple graph (without the weight and direction).