halozatrombolas/destroy_p3.py

import numpy as np
import networkx as nx
import argparse

parser = argparse.ArgumentParser(description='')
parser.add_argument('-g', '--graph', dest='graph', action='store', default=None)
args = parser.parse_args()

if not args.graph:
    print("need a graph as input")
    exit()


def read_graph(graph_file):
    with open(graph_file) as f:
        n = int(f.readline())
        m = int(f.readline())
        A = [[0] * n for _ in range(n)]
        for _ in range(m):
            [u, v] = map(int, f.readline().split())
            A[u][v] = 1
            A[v][u] = 1
    G = nx.Graph(np.array(A))
    return G


def max_comp_size(G):
    return max([len(c) for c in nx.connected_components(G)])


del_list = []
G = read_graph(args.graph)
n = len(G.nodes)
while max_comp_size(G) > n / 2:
    u = np.random.choice(G.nodes)
    if u not in del_list:
        del_list.append(u)
        G.remove_node(u)

# print len(del_list), del_list


for u in del_list:
    print(u)