广度优先搜索，Python代码如下，搞清楚二维数组里的横纵坐标，这类题很简单：

class Queue(object):
    def __init__(self):
        self.items = []
        self.head = 0
        self.tail = 0
    def append(self,node):
        self.items.append(node)
        self.tail += 1
    def get(self):
        return self.items[self.head]
map_list = [
    [1,2,1,0,0,0,0,0,2,3],
    [3,0,2,0,1,2,1,0,1,2],
    [4,0,1,0,1,2,3,2,0,1],
    [3,2,0,0,0,1,2,4,0,0],
    [0,0,0,0,0,0,1,5,3,0],
    [0,1,2,1,0,1,5,4,3,0],
    [0,1,2,3,1,3,6,2,1,0],
    [0,0,3,4,8,9,7,5,0,0],
    [0,0,0,3,7,8,6,0,1,2],
    [0,0,0,0,0,0,0,0,1,0]
]
x,y = 7,5
next = [[0,1],[1,0],[0,-1],[-1,0]]
#已达点
book_list = []
#初始化
can_arrive = Queue()
can_arrive.append((7,5))

while can_arrive.head<can_arrive.tail: #到达最后一个节点
    #获得一个点，遍历该点可达点
    x,y = can_arrive.get()[0],can_arrive.get()[1]
    #正在遍历的该点，已经到达，放入到已达点列表
    book_list.append((x, y))
    #依次为前后左右
    for j in range(4):
        #下一点的横坐标
        tx = x + next[j][1]
        #下一点的纵坐标
        ty = y + next[j][0]
        #判定，越界？，已达？
        if 0<=tx<=9 and 0<=ty<=9 and (tx,ty) not in book_list:
            if map_list[tx][ty] != 0 and (tx,ty) not in can_arrive.items:
                #将该点放到可达列表，准备遍历
                can_arrive.append((tx,ty))
    #头指针后移
    can_arrive.head +=1

if __name__ == '__main__':
    print(can_arrive.items)

深度优先搜索代码：

import sys
sys.setrecursionlimit(100000)
map_list = [
    [1,2,1,0,0,0,0,0,2,3],
    [3,0,2,0,1,2,1,0,1,2],
    [4,0,1,0,1,2,3,2,0,1],
    [3,2,0,0,0,1,2,4,0,0],
    [0,0,0,0,0,0,1,5,3,0],
    [0,1,2,1,0,1,5,4,3,0],
    [0,1,2,3,1,3,6,2,1,0],
    [0,0,3,4,8,9,7,5,0,0],
    [0,0,0,3,7,8,6,0,1,2],
    [0,0,0,0,0,0,0,0,1,0]
]
next = [[0,1],[1,0],[0,-1],[-1,0]]
#已达点
book_list = []
#初始化
can_arrive = [(7,5)]
def dfs(x,y):
    book_list.append((x, y))
    for i in range(4):
        tx = x + next[i][1]
        ty = y + next[i][0]
        #判定
        if 0<=tx<=9 and 0<=ty<=9 and (tx,ty) not in book_list:
            if map_list[tx][ty]!=0:
                if (tx,ty) not in can_arrive:
                    can_arrive.append((tx,ty))
                dfs(tx,ty)
    #book_list.remove((x,y))
if __name__ == '__main__':
    dfs(7,5)
    print(can_arrive)
    print(len(can_arrive))

?