# Dijkstra’s algorithm in python

As others have pointed out, due to not using understandable variable names, it is almost impossible to debug your code.

Following the wiki article about Dijkstra’s algorithm, one can implement it along these lines (and in a million other manners):

```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]
current, currentDistance = sorted(candidates, key = lambda x: x)

print(visited)

```

This code is more verbous than necessary and I hope comparing your code with mine you might spot some differences.

The result is:

```{'E': 2, 'D': 1, 'G': 2, 'F': 4, 'A': 4, 'C': 3, 'B': 0}
```