//https://leetcode.com/problems/is-graph-bipartite/
/*
* Given an undirected graph, return true if and only if it is bipartite.
*
* Recall that a graph is bipartite if we can split it's set of nodes into two independent subsets A and B such that every edge in the graph has one node in A and another node in B.
*
* The graph is given in the following form: graph[i] is a list of indexes j for which the edge between nodes i and j exists. Each node is an integer between 0 and graph.length - 1. There are no self edges or parallel edges: graph[i] does not contain i, and it doesn't contain any element twice.
*/
public bool IsBipartite(int[][] adjacencyMatrix)
{
var nodes = new HashSet <GraphNode <int> >();
var edges = new List <UndirectedEdge <int> >();
for (int i = 0; i < adjacencyMatrix.GetLength(0); i++)
{
for (int j = 0; j < adjacencyMatrix[i].Length; j++)
{
var node_i = new GraphNode <int>(i);
node_i = nodes.TryGetValue(node_i, out var node) ? node : node_i;
nodes.Add(node_i);
var node_j = new GraphNode <int>(adjacencyMatrix[i][j]);
node_j = nodes.TryGetValue(node_j, out node) ? node : node_j;
nodes.Add(node_j);
edges.Add(new UndirectedEdge <int>(node_i, node_j));
}
}
var graph = new UndirectedGraph <int>(nodes, edges);
return(GraphProperties <int> .IsBipartite(graph));
}
public void IsBipartite(TestData testGraph) => Assert.Equal(testGraph.IsBipartite, GraphProperties.IsBipartite(testGraph.Graph));
