在python中实现Karger的最小割算法时,我得到输出为
edgelist remaining: [[11, 20], [11, 20], [20, 11], [20, 11], [20, 11]]
nodelist remaining: [11, 20]
这是否意味着最低限额为5?我使用以下代码:
with open('foo1.txt') as req_file:
mincut_data = []
for line in req_file:
line = line.split()
if line:
line = [int(i) for i in line]
mincut_data.append(line)
#extracting edges from the data #
edgelist = []
nodelist = []
for every_list in mincut_data:
nodelist.append(every_list[0])
temp_list = []
for temp in range(1,len(every_list)):
temp_list = [every_list[0], every_list[temp]]
flag = 0
for ad in edgelist:
if set(ad) == set(temp_list):
flag = 1
if flag == 0 :
edgelist.append([every_list[0],every_list[temp]])
#karger min cut algorithm#
while(len(nodelist) > 2):
val = randint(0,(len(edgelist)-1))
print (val)
target_edge = edgelist[val]
replace_with = target_edge[0]
should_replace = target_edge[1]
for edge in edgelist:
if(edge[0] == should_replace):
edge[0] = replace_with
if(edge[1] == should_replace):
edge[1] = replace_with
nodelist.remove(should_replace)
for i in range((len(edgelist)-1),-1,-1):
if edgelist[i][0] == edgelist[i][1]:
edgelist.remove(edgelist[i])
print ('edgelist remaining: ',edgelist)
print ('nodelist remaining: ',nodelist)
我正在尝试在python中学习Karger的算法,但我不确定这是否正确。
答案 0 :(得分:0)
我找到了答案。剩下的边缘列表似乎是最小的切割。由于Karger的算法是一个随机算法,程序需要多次运行以获得最佳解决方案。