/Python/Python dijkstra implementation stack

Python dijkstra implementation stack

nodes = ('A', 'B', 'C', 'D', 'E', 'F', 'G')
distances = {
    'B': {'A': 5, 'D': 1, 'G': 2},
    'A': {'B': 5, 'D': 3, 'E': 12, 'F' :5},
    'D': {'B': 1, 'G': 1, 'E': 1, 'A': 3},
    'G': {'B': 2, 'D': 1, 'C': 2},
    'C': {'G': 2, 'E': 1, 'F': 16},
    'E': {'A': 12, 'D': 1, 'C': 1, 'F': 2},
    'F': {'A': 5, 'E': 2, 'C': 16}}

unvisited = {node: None for node in nodes} #using None as +inf
visited = {}
current = 'B'
currentDistance = 0
unvisited[current] = currentDistance

while True:
    for neighbour, distance in distances[current].items():
        if neighbour not in unvisited: continue
        newDistance = currentDistance + distance
        if unvisited[neighbour] is None or unvisited[neighbour] > newDistance:
            unvisited[neighbour] = newDistance
    visited[current] = currentDistance
    del unvisited[current]
    if not unvisited: break
    candidates = [node for node in unvisited.items() if node[1]]
    current, currentDistance = sorted(candidates, key = lambda x: x[1])[0]

print(visited)

Source: stackoverflow.com

Similar codes

0 vote164 views1 answer
How to make a var in pycode
Python
4 votes153 views1 answer
How to add column headers in pandas
Python
0 vote170 views1 answer
Boolien in python
Python
1 vote163 views1 answer
Convert list of values to dictionary based on count
Python
0 vote114 views1 answer
Index is datetime and i want the row number
Python
1 vote188 views1 answer
Django loop index
Python Django
8 votes167 views1 answer
Convert pandas series from str to int
Python
0 vote171 views1 answer
Django queryset with multiple contain keyword
Python
1 vote157 views1 answer
Isistance exmaple
Python
6 votes174 views3 answers
Pandas to csv without header
Python