Dynamic Programming--minium span tree

標籤：

graph=[
[0,   1,   999,  9, 999],
[1,   0,   5,    7,   3],
[999, 5,   0,    999, 4],
[9 ,  7,   999,  0,   3],
[999, 1,   999,  9, 999]
]

for i in range(0,5):
 print graph[i]

points =[‘A‘, ‘B‘, ‘C‘, ‘D‘, ‘E‘]
selected =[]

def is_not_selected(i):
 if i in selected:
  return False
 else:
  return True

edges = []
#1 find the shortest edge
#2 add the points of edge into selected set
#3 in the selected set, add the shortest edge with one point in the selected set,while the other is not 
def get_minium_tree(edges):
 k=0
 while k<100:
  min=1000
  curi = -1
  curj = -1
  for i in range(0,5):
   for j in range(0,5):
    if ((i !=j) and (is_not_selected(i) or is_not_selected(j))):
     if min>graph[i][j] :
      min= graph[i][j]
      curi =i
      curj = j
  if ((curi == -1) or (curj == -1)):
   break
  if is_not_selected(curi):
   selected.append(curi)
  if is_not_selected(curj):
   selected.append(curj)
  edges.append([points[curi], points[curj]])
  k=k+1

get_minium_tree(edges)

print edges

 

Dynamic Programming--minium span tree