Graphs

AdjacentList.m

@interface TSGraph : NSObject

- (void)addEdgeFrom:(id)vertexA to:(id)vertexB;

@end

@implementation TSGraph
{
    NSMutableDictionary *_vertices;
}

- (instancetype)init
{
    if ((self = [super init])) {
        _vertices = [NSMutableDictionary dictionary];
    }

    return self;
}

- (void)addEdgeFrom:(id)vertexA to:(id)vertexB
{
    NSMutableArray *edges = _vertices[vertexA];
    if (!edges) {
        edges = [NSMutableArray array];
        _vertices[vertexA] = edges;
    }

    [edges addObject:vertexB];
}

@end