Dijkstra Algorithm

from collections import defaultdict as dd
import heapq as hq
class Solution:

    #Function to find the shortest distance of all the vertices
    #from the source vertex S.
    def dijkstra(self, v, g, s):
        adj=dd(list)
        for i in range(v):
            for j,w in g[i]:
                adj[i].append((j,w))

        vis=set()
        dis=[1e9]*v
        dis[s]=0
        vis=set()
        h=[(0,s)]
        while h:
            w1,n1=hq.heappop(h)
            if n1 in vis: continue
            vis.add(n1)
            for n2,w2 in adj[n1]:
                if n2 in vis:continue
                if dis[n2]>w1+w2:
                    dis[n2]=w1+w2
                    hq.heappush(h,(dis[n2],n2))
        return dis