python最小生成樹kruskal與prim算法詳解

#coding=utf-8
class Graph(object):
  def __init__(self, maps):
    self.maps = maps
    self.nodenum = self.get_nodenum()
    self.edgenum = self.get_edgenum()
 
  def get_nodenum(self):
    return len(self.maps)
 
  def get_edgenum(self):
    count = 0
    for i in range(self.nodenum):
      for j in range(i):
        if self.maps[i][j] > 0 and self.maps[i][j] < 9999:
          count += 1
    return count
 
  def kruskal(self):
    res = []
    if self.nodenum <= 0 or self.edgenum < self.nodenum-1:
      return res
    edge_list = []
    for i in range(self.nodenum):
      for j in range(i,self.nodenum):
        if self.maps[i][j] < 9999:
          edge_list.append([i, j, self.maps[i][j]])#按[begin, end, weight]形式加入
    edge_list.sort(key=lambda a:a[2])#已經(jīng)排好序的邊集合
    
    group = [[i] for i in range(self.nodenum)]
    for edge in edge_list:
      for i in range(len(group)):
        if edge[0] in group[i]:
          m = i
        if edge[1] in group[i]:
          n = i
      if m != n:
        res.append(edge)
        group[m] = group[m] + group[n]
        group[n] = []
    return res
 
  def prim(self):
    res = []
    if self.nodenum <= 0 or self.edgenum < self.nodenum-1:
      return res
    res = []
    seleted_node = [0]
    candidate_node = [i for i in range(1, self.nodenum)]
    
    while len(candidate_node) > 0:
      begin, end, minweight = 0, 0, 9999
      for i in seleted_node:
        for j in candidate_node:
          if self.maps[i][j] < minweight:
            minweight = self.maps[i][j]
            begin = i
            end = j
      res.append([begin, end, minweight])
      seleted_node.append(end)
      candidate_node.remove(end)
    return res
 
max_value = 9999
row0 = [0,7,max_value,max_value,max_value,5]
row1 = [7,0,9,max_value,3,max_value]
row2 = [max_value,9,0,6,max_value,max_value]
row3 = [max_value,max_value,6,0,8,10]
row4 = [max_value,3,max_value,8,0,4]
row5 = [5,max_value,max_value,10,4,0]
maps = [row0, row1, row2,row3, row4, row5]
graph = Graph(maps)
print('鄰接矩陣為\n%s'%graph.maps)
print('節(jié)點(diǎn)數(shù)據(jù)為%d，邊數(shù)為%d\n'%(graph.nodenum, graph.edgenum))
print('------最小生成樹kruskal算法------')
print(graph.kruskal())
print('------最小生成樹prim算法')
print(graph.prim())