303 lines
12 KiB
Python
303 lines
12 KiB
Python
#!/usr/bin/env python -O
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#-*-coding:big5-*-
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#Author:chen, chien-ting
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#Updated Day:2011-04-26
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#license: GPL (http://www.gnu.org/licenses/gpl.html)
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'''
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WARNING:
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The usage of the program MAY NOT violate the laws, and the author of the
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program DOES NOT have the responsibility for the usage of other users.
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'''
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import re #regular expression
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import sys #used to control system
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import os #used to detect the system information
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os_name = os.name #the type of operating system (posix, nt, and so on).
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'''funtcion to quit the program'''
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def quit_program():
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a = raw_input("請按 Enter 鍵繼續...")
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exit()
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'''open data file'''
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raw_data_file = open('in.txt','r').readlines() #open the data file(in.txt) and spilt it by line.
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raw_database = [] #raw_database
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'''transfer raw_data_file to raw_database'''
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for i in range(len(raw_data_file)):
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line = raw_data_file[i] #content of line i of raw_data_file.
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#ignore empty line.
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if re.match ('^\s*$', line):
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pass
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#ignore lines with unnacessary data.
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elif re.match('^\S+$',line):
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pass
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elif re.match('^\s*[^#]', line): #avoid import commends (starts with #) and null line
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line = re.split('#', line)[0] #ignore commend (starts with #)
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line_splitted = re.split('\s+', line) #split it with space, tab, and linefeed.
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'''delete the null string splitted improperly by linefeed character.'''
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if line_splitted[-1] == '':
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del line_splitted[-1]
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'''if the data item is/are too many or too few, print the error.'''
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if len(line_splitted) != 3:
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print "第 %d 行的資料不足或過多，請檢查資料內容是否正確。"\
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% (i + 1)
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print line_splitted
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quit_program()
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'''try to convert the distance to float'''
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try:
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line_splitted[2] = float(line_splitted[2])
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#If the distance can't be floated, print the error.
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except ValueError:
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print "第 %d 行的距離（或其他成本）之資料錯誤！請檢查該資料是否有誤。" % (i + 1)
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quit_program()
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else:
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raw_database.append(line_splitted) #append the line to the raw_database
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else:
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pass
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'''convert the raw files.'''
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origin = [""] #all the origin points are stored here
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all_point = [""] #all the points are stored here
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origin_pointer = [""] #pointer for origin points.
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destination_and_distance = [] #destination and distance point table of star forward format
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for i in range(len(raw_database)):
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for j in range(len(origin)):
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if raw_database[i][0] == origin[j]:
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break
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elif raw_database[i][0] != origin[j] and j == len(origin) - 1:
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if origin == [""]:
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origin = [raw_database[i][0]]
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else:
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origin.append(raw_database[i][0])
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else:
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pass
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'''create all point list'''
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for i in range(len(raw_database)):
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for j in [0, 1]:
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for k in range(len(all_point)):
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if raw_database[i][j] == all_point[k]:
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break
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elif (raw_database[i][j] != all_point[k] \
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and k == len(all_point) - 1):
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if all_point == [""]:
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all_point = [raw_database[i][j]]
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else:
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all_point.append(raw_database[i][j])
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else:
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pass
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'''create destination and distance data for forward_star form'''
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for i in range(len(origin)):
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#create template list storing destination and distace of a origin.
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template_dest_dist = []
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for j in range (len(raw_database)):
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if raw_database[j][0] == origin[i]:
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#add the destination and distance data in the template
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#list.
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template_dest_dist.append(raw_database[j][1:])
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#key in the origin pointer
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if origin_pointer == [""]:
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origin_pointer = [1]
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origin_pointer.append(origin_pointer[-1] + len(template_dest_dist))
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for i in range(len(template_dest_dist)):
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destination_and_distance.append(template_dest_dist[i])
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del(origin_pointer[-1]) #delete one pointer not needed.
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print "star forward的形式如下（自1起算）："
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'''Print Start'''
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print "起點序列如下："
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for i in range(len(origin)):
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#print i and comma without creating newline
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sys.stdout.write(origin[i])
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#don't print comma in front of last item.
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if i != len(origin)-1 :
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sys.stdout.write(', ')
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print '\n'
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print "起點指標如下："
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print origin_pointer, '\n'
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'''Print destination and distance'''
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print "迄點與距離如下："
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print "迄點", "\t", "距離或成本"
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print "-------------------------------"
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for i in destination_and_distance:
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print i[0], "\t", i[1]
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print "\n"
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'''find the shortest_path'''
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choice = "" #user's choice to find hte shortest path or not
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while (re.match("^yes\s*$",choice) == None) and (re.match("^no\s*$",choice) == None): #\n = linefeed
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print "您想要求得最短路徑嗎？(yes or no)"
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choice = raw_input("\n>>>") #user's choice
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if re.match("^no\s*$",choice):
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pass
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else:
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point_number_of_start_in_all_point = None #an interger start from 0!
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while point_number_of_start_in_all_point == None:
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start = raw_input("請輸入起點：")
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for i in range(len(all_point)):
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if start == all_point[i]:
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point_number_of_start_in_all_point = i
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break
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point_number_of_goal_in_all_point = None #an interger start from 0!
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while point_number_of_goal_in_all_point == None:
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goal = raw_input("請輸入終點：")
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for i in range(len(all_point)):
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if goal == all_point[i]:
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point_number_of_goal_in_all_point = i
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break
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inf = float("infinity") #define inf as +infinity.
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distance_from_start_to_all_point = [inf] * len(all_point) #d(x). inf = infinite
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distance_from_start_to_all_point[point_number_of_start_in_all_point] = 0 #when x = s, d(x) = 0
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previous_point_from_start_to_above = ["unknown"] * len(all_point)
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previous_point_from_start_to_above[point_number_of_start_in_all_point] = None #when x = s, path(x) = none
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y = [start] #y[-1] = real y; other item of y = historical y.
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while y[-1] != goal:
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for i in range(len(all_point)):
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if y[-1] == all_point[i]:
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point_number_of_y_in_all_point = i
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break
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point_number_of_y_in_origin = None
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for i in range(len(origin)):
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if y[-1] == origin[i]:
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point_number_of_y_in_origin = i #starts from 0
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break
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'''refreshing d(x)'''
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for x in range(len(all_point)):
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'''find a(y,x) of each x'''
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a_of_y_x = inf #value of a(y,x)
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if point_number_of_y_in_origin != None:
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index_begin = (origin_pointer[point_number_of_y_in_origin]-1)
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if point_number_of_y_in_origin == len(origin_pointer) - 1:
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index_end = len(destination_and_distance) - 1
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else:
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index_end = (origin_pointer[(point_number_of_y_in_origin)+1]-1)
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for i in range(index_begin, index_end):
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if x == destination_and_distance[i][1]:
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a_of_y_x = destination_and_distance[i][1]
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'''refreshing d(x)'''
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distance_from_s_to_y = distance_from_start_to_all_point[point_number_of_y_in_all_point] #d(y)
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d_of_y_plus_a_of_y_x = distance_from_s_to_y + a_of_y_x #d(y)+a(y,x)
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'''min{d(x),d(y)+a(y,x)}'''
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if distance_from_start_to_all_point[x] >= d_of_y_plus_a_of_y_x:
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distance_from_start_to_all_point[x] = d_of_y_plus_a_of_y_x
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'''refresh path(x)'''
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if a_of_y_x != inf:
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previous_point_from_start_to_above[x] = all_point[point_number_of_y_in_all_point]
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else:
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pass
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'''refreshing y[-1]'''
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number_of_template_y_in_all_points = 0
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min_of_d_x_and_x_not_y = inf #use an infinite and used it to decrease some time to find the min.
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for i in range(len(distance_from_start_to_all_point)):
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for j in y:
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if all_point[i] == j:
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#print "i = %d break"% i
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#print "min_of_d_x_and_x_not_y %f" % min_of_d_x_and_x_not_y
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break
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elif all_point[i] != j and j == y[len(y)-1]:
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#print "i %d" % i
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#print "min_of_d_x_and_x_not_y %f" % min_of_d_x_and_x_not_y
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if min_of_d_x_and_x_not_y >= distance_from_start_to_all_point[i]:
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min_of_d_x_and_x_not_y = distance_from_start_to_all_point[i]
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number_of_template_y_in_all_points = i
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#print "number_of_template_y_in_all_points %s" % number_of_template_y_in_all_points
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else:
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pass
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y.append(all_point[number_of_template_y_in_all_points])
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#print y
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#print 'path', previous_point_from_start_to_above
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else:
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print "找到 %s 到 %s 的最短路徑，" % (start, goal)
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'''Print the shortest length. However, if it\'s infinity, print "infinitely long"'''
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if distance_from_start_to_all_point[point_number_of_goal_in_all_point] != inf:
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print "長度： %s" % distance_from_start_to_all_point[point_number_of_goal_in_all_point]
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else:
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print "長度： 無限長"
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print "路徑如下："
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previous_point = previous_point_from_start_to_above[point_number_of_goal_in_all_point]
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if distance_from_start_to_all_point[point_number_of_goal_in_all_point] != inf:
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route_path = [previous_point, goal]
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while previous_point != start:
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for i in range(len(all_point)):
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if all_point[i] == previous_point:
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previous_point = previous_point_from_start_to_above[i]
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route_path.insert(0, previous_point)
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for i in range(len(route_path)):
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sys.stdout.write(route_path[i])
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if i != len(route_path) - 1:
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sys.stdout.write(" -> ") #sys.stdout.write means print something without creating newline.
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else:
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sys.stdout.write("\n")
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else:
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print "找不到連絡的路徑！"
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quit_program()
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