回溯法（探索与回溯法）是一种选优搜索法，又称为试探法，按选优条件向前搜索，以达到目标。但当探索到某一步时，发现原先选择并不优或达不到目标，就退回一步重新选择，这种走不通就退回再走的技术为回溯法，而满足回溯条件的某个状态的点称为“回溯点”。

我们用回溯法来写迷宫问题，如下：

maze = [[0, 0, 1, 1, 1, 1, 1, 1],
        [1, 0, 1, 0, 1, 1, 0, 1],
        [1, 0, 0, 1, 1, 1, 0, 1],
        [1, 0, 1, 0, 0, 0, 0, 1],
        [1, 0, 0, 0, 1, 0, 1, 1],
        [1, 1, 1, 0, 1, 0, 1, 1],
        [1, 0, 0, 0, 1, 0, 0, 1],
        [1, 1, 1, 1, 1, 1, 0, 1]]

stack = []
dirs = [(0, 1), (1, 0), (0, -1), (-1, 0)]
def mark(m, p):
    m[p[0]][p[1]] = 2
def judge(m, p):
    return m[p[0]][p[1]] == 0
def maze_solver(m, s, e):
    if s == e:
        print(s)
        return
    mark(m, s)
    stack.append(s)
    while len(stack):
        pos = stack[-1]
        stack.pop()
        for i in range(4):
            nextp = (pos[0] + dirs[i][0], pos[1] + dirs[i][1])
            if nextp == e:
                print("路径：", stack)
                return
            if judge(m, nextp):
                stack.append(pos)
                mark(m, nextp)
                stack.append(nextp)
                break
    print("找不到路径")
for i in range(8):
    for j in range(8):
        print(maze[i][j], end='')
    print()
maze_solver(maze, s=(0, 0), e=(7, 7))