skynetVirus | Python Fiddle

import sys, math

def bfs_paths(graph, start, goal):
    queue = [(start, [start])]
    while queue:
        (vertex, path) = queue.pop(0)
        for next in graph[vertex] - set(path):
            if next in goal:
                yield path + [next]
            else:
                queue.append((next, path + [next]))

def shortest_path(graph, start, goal):
    try:
        return next(bfs_paths(graph, start, goal))
    except StopIteration:
        return None  
        
def severRoute(route, graph):
    graph[rout[0]].remove
# Auto-generated code below aims at helping you parse
# the standard input according to the problem statement.

# N: the total number of nodes in the level, including the gateways
# L: the number of links
# E: the number of exit gateways
N, L, E = [int(i) for i in raw_input().split()]
graph = {}
for i in xrange(L):
    # N1: N1 and N2 defines a link between these nodes
    n1,n2 = [int(j) for j in raw_input().split()]
    if n1 in graph:
        graph[n1].add(n2)
    else:
        graph[n1] = set([n2])
        
    if n2 in graph:
        graph[n2].add(n1)
    else:
        graph[n2] = set([n1])
        
gateways = [int(raw_input()) for k in xrange(E)] # the index of a gateway node
print >>sys.stderr, "Gateways: "+ str(gateways)
# game loop
while 1:
    agent = int(raw_input()) # The index of the node on which the Skynet agent is positioned this turn
    likelyRoute = shortest_path(graph,agent,gateways)
    print >>sys.stderr,"Likely agent route: "+ str(likelyRoute)
    # Write an action using print
    # To debug: print >> sys.stderr, "Debug messages..."
    severedLink = severRoute(likelyRoute,graph)
    print >>sys.stderr,"severed link: "+ str(severedLink)
    print severedLink[0]+" "+severedLink[1] # Example: 0 1 are the indices of the nodes you wish to sever the link between

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