--- id: 65578fcf00322dbad5dee05b title: Step 43 challengeType: 20 dashedName: step-43 --- # --description-- Create an `if` statement to check if the distance of the neighbor node (the second item in the processed tuple) plus the distance of `current` is less than the currently known distance of the neighbor node (the first item in the processed tuple). Use the `pass` keyword to temporarily fill the body of the `if`. # --hints-- You should have an `if` statement to check if `distance + distances[current]` is less than `distances[node]`. ```js ({ test: () => { const shortest = __helpers.python.getDef(code, "shortest_path"); const {function_body} = shortest; assert(function_body.match(/^(\s*)for\s+\w+\s*,\s*\w+\s+in\s+graph\s*\[\s*current\s*\]\s*:\s*^\1(\s{4})if\s+distance\s*\+\s*distances\s*\[\s*current\s*\]\s*<\s*distances\s*\[\s*node\s*\]\s*:/ms)); } }) ``` # --seed-- ## --seed-contents-- ```py my_graph = { 'A': [('B', 3), ('D', 1)], 'B': [('A', 3), ('C', 4)], 'C': [('B', 4), ('D', 7)], 'D': [('A', 1), ('C', 7)] } def shortest_path(graph, start): unvisited = list(graph) distances = {node: 0 if node == start else float('inf') for node in graph} paths = {node: [] for node in graph} paths[start].append(start) while unvisited: current = min(unvisited, key=distances.get) --fcc-editable-region-- for node, distance in graph[current]: pass --fcc-editable-region-- print(f'Unvisited: {unvisited}\nDistances: {distances}\nPaths: {paths}') #shortest_path(my_graph, 'A') ```