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Objective-C实现Dijkstra算法的示例代码
Dijkstra算法是一种有效的单源最短路径算法,广泛应用于交通网络、地图导航等领域。以下是使用Objective-C实现Dijkstra算法的示例代码,帮助开发者理解如何在实际项目中应用该算法。
通过代码示例可以看到,实现Dijkstra算法的主要步骤如下:
以下是代码示例的核心部分:
#import@interface Graph : NSObject@property (nonatomic, strong) NSMutableDictionary *edges;@end@implementation Graph- (void)addEdgeFrom:(NSString *)from to:(NSString *)to weight:(double)weight { [self.edges setValue:weight forKey:from]; [self.edges setValue:weight forKey:to];}- (void)dijsktraFrom:(NSString *)start { // 初始化最短路径数组 NSMutableDictionary *distances = [NSMutableDictionary dictionary]; // 设置起始节点距离为0,其他节点为无穷大 [distances setValue:@0 forKey:start]; // 使用优先队列存储节点 NSMutableArray *queue = [NSMutableArray array]; [queue addObject:start]; while (!queue.isEmpty) { // 提取当前最短路径的节点 NSString *current = [self minNodeInQueue:queue]; double currentDistance = [distances valueForKey:current]; // 遍历当前节点的所有邻接节点 for (NSString *neighbor in [self edges]) { if ([neighbor isEqualToString:current]) continue; double weight = [self.edges valueForKey:neighbor]; double newDistance = currentDistance + weight; if ([distances valueForKey:neighbor] > newDistance) { [distances setValue:newDistance forKey:neighbor]; [queue addObject:neighbor]; } } } return distances;}- (NSString *)minNodeInQueue:(NSMutableArray *)queue { if (queue.count == 0) return nil; // 通过比较节点名称,取距离最小的节点 id min = nil; double minDistance = INFINITY; for (id node in queue) { double distance = [self.distances valueForKey:(NSString *)node]; if (distance < minDistance) { minDistance = distance; min = node; } } return (NSString *)min;}- (NSDictionary *)edges { return [self.edges copy];}
该代码实现了以下功能:
通过上述实现,可以轻松地在Objective-C项目中应用Dijkstra算法,解决实际的最短路径问题。
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