An implementation of dijkstra made by GPTo3-mini-high

graphes/homework_wednesday.py

@@ -0,0 +1,55 @@
+# Chatgpt code
+
+import heapq
+
+def dijkstra(graph, source):
+    distances = {node: float('inf') for node in graph}
+    distances[source] = 0
+    
+    previous = {node: None for node in graph}
+    
+    queue = [(0, source)]
+    
+    while queue:
+        current_distance, current_node = heapq.heappop(queue)
+        
+        if current_distance > distances[current_node]:
+            continue
+        
+        for neighbor, weight in graph[current_node]:
+            distance = current_distance + weight
+            if distance < distances[neighbor]:
+                distances[neighbor] = distance
+                previous[neighbor] = current_node
+                heapq.heappush(queue, (distance, neighbor))
+    
+    return distances, previous
+
+def reconstruct_path(previous, start, end):
+    path = []
+    node = end
+    while node is not None:
+        path.append(node)
+        node = previous[node]
+    path.reverse()
+    return path
+
+if __name__ == '__main__':
+    graph = {
+        "R1": [("R2", 1)],
+        "R2": [("R3", 1), ("R5", 10)],
+        "R3": [("R4", 1), ("R5", 1)],
+        "R5": [("R4", 10)],
+        "R4": []
+    }
+    
+    source = "R1"
+    destination = "R4"
+    
+    distances, previous = dijkstra(graph, source)
+    
+    print("Shortest distances from", source, ":", distances)
+    
+    path = reconstruct_path(previous, source, destination)
+    print("Shortest path from", source, "to", destination, ":", path)
+