Python/data_structures/Graph/Dijkstra.py

58 lines
1.2 KiB
Python

from __future__ import print_function
def printDist(dist, V):
print("\nVertex Distance")
for i in range(V):
if dist[i] != float('inf') :
print(i,"\t",int(dist[i]),end = "\t")
else:
print(i,"\t","INF",end="\t")
print();
def minDist(mdist, vset, V):
minVal = float('inf')
minInd = -1
for i in range(V):
if (not vset[i]) and mdist[i] < minVal :
minInd = i
minVal = mdist[i]
return minInd
def Dijkstra(graph, V, src):
mdist=[float('inf') for i in range(V)]
vset = [False for i in range(V)]
mdist[src] = 0.0;
for i in range(V-1):
u = minDist(mdist, vset, V)
vset[u] = True;
for v in range(V):
if (not vset[v]) and graph[u][v]!=float('inf') and mdist[u] + graph[u][v] < mdist[v]:
mdist[v] = mdist[u] + graph[u][v]
printDist(mdist, V)
#MAIN
V = int(input("Enter number of vertices: "));
E = int(input("Enter number of edges: "));
graph = [[float('inf') for i in range(V)] for j in range(V)]
for i in range(V):
graph[i][i] = 0.0;
for i in range(E):
print("\nEdge ",i+1)
src = int(input("Enter source:"))
dst = int(input("Enter destination:"))
weight = float(input("Enter weight:"))
graph[src][dst] = weight;
gsrc = int(input("\nEnter shortest path source:"))
Dijkstra(graph, V, gsrc)