迷宮問題之深搜
#!/usr/bin/python3
# 檔名: StackClass.py
from StackClass import ListStack,LinkStack
OPEN, CLOSE, PASSED, ROAD = 0, 1, 2, -1 #分別表示該點通，不通，已走和屬於所選路徑
dirs = ((0, 1), (1, 0), (0, -1), (-1, 0)) #分別向東南西北走的行列座標變換情況
def mark(maze, pos):
maze[pos[0]][pos[1]] = PASSED
def passable(maze, pos): #判斷當前位置是否可通行
return maze[pos[0]][pos[1]] == OPEN
def find_path(maze, pos, end): #遞迴演算法
mark(maze, pos)
if pos == end:
print(pos, end = " ")
return True
for i in range(4):
nextp = (pos[0]+dirs[i][0], pos[1]+dirs[i][1])
if passable(maze, nextp) and find_path(maze, nextp, end):
print(pos, end = " ")
return True
return False
def print_path(end, pos, s):#逆序輸出路徑
print(end, end = " ")
print(pos, end = " ")
while not s.is_empty():
print(s.pop()[0], end = " ")
def deepSearch(maze, start, end): #非遞迴演算法
if start == end:
print(start)
return True
s = ListStack()
mark(maze, start)
s.push((start, 0))
while not s.is_empty():
pos, nxt = s.pop()
for i in range(nxt, 4): #依次檢查未探查方向
nextp = (pos[0]+dirs[i][0], pos[1]+dirs[i][1])
if nextp == end:
print_path(end, pos, s) #輸出路徑，注意此時end和pos不在棧中，需要單獨輸出
return True
if passable(maze, nextp):
s.push((pos, i+1)) #原位置和下一方向入棧
mark(maze, nextp)
s.push((nextp, 0)) #新位置入棧
break #退出內層迴圈，處理下一位置
return False
maze = [[1,1,1,1,1,1,1,1,1,1,1,1,1,1],
[1,0,0,0,1,1,0,0,0,1,0,0,0,1],
[1,0,1,0,0,0,0,1,0,1,0,1,0,1],
[1,0,1,0,1,1,1,1,0,1,0,1,0,1],
[1,0,1,0,0,0,0,1,0,1,1,1,0,1],
[1,0,1,1,1,1,1,1,1,1,0,0,0,1],
[1,0,1,0,0,0,0,0,0,0,0,1,0,1],
[1,0,0,0,1,1,1,0,1,0,1,1,0,1],
[1,0,1,0,1,0,1,0,1,0,1,0,0,1],
[1,0,1,0,1,0,1,0,1,1,1,1,0,1],
[1,0,1,0,0,0,1,0,0,1,0,0,0,1],
[1,1,1,1,1,1,1,1,1,1,1,1,1,1]]
start = (1, 1)
end = (10, 12)
find_path(maze, start, end)
print()
maze = [[1,1,1,1,1,1,1,1,1,1,1,1,1,1],
[1,0,0,0,1,1,0,0,0,1,0,0,0,1],
[1,0,1,0,0,0,0,1,0,1,0,1,0,1],
[1,0,1,0,1,1,1,1,0,1,0,1,0,1],
[1,0,1,0,0,0,0,1,0,1,1,1,0,1],
[1,0,1,1,1,1,1,1,1,1,0,0,0,1],
[1,0,1,0,0,0,0,0,0,0,0,1,0,1],
[1,0,0,0,1,1,1,0,1,0,1,1,0,1],
[1,0,1,0,1,0,1,0,1,0,1,0,0,1],
[1,0,1,0,1,0,1,0,1,1,1,1,0,1],
[1,0,1,0,0,0,1,0,0,1,0,0,0,1],
[1,1,1,1,1,1,1,1,1,1,1,1,1,1]]
deepSearch(maze, start, end)