Go: package main

import (
	"bufio"
	"container/list"
	"fmt"
	"os"
	"strconv"
	"strings"
)

func main() {
	io := NewIo()
	defer io.Flush()
	for {
		w, h := io.NextInt(), io.NextInt()
		if w == 0 {
			break
		}
		xWall := make([][]int, h)
		yWall := make([][]int, h)
		for i := 0; i < h; i++ {
			xWall[i], yWall[i] = make([]int, w), make([]int, w)
			for j := 0; j < w; j++ {
				xWall[i][j], yWall[i][j] = -1, -1
			}
		}
		for i := 0; i < h*2-1; i++ {
			if i%2 == 0 {
				for j := 0; j < w-1; j++ {
					xWall[i/2][j] = io.NextInt()
				}
			} else {
				for j := 0; j < w; j++ {
					yWall[i/2][j] = io.NextInt()
				}
			}
		}
		//io.Println(bfs(w, h, xWall, yWall))
		fmt.Println(bfs(w, h, xWall, yWall))
	}
}

type P struct {
	x, y int
}

func bfs(w, h int, x, y [][]int) int {
	d := make([][]int, h)
	for i := 0; i < h; i++ {
		d[i] = make([]int, w)
	}
	q := list.New()
	q.PushBack(P{0, 0})
	d[0][0] = 1

	for q.Len() != 0 {
		pos := q.Remove(q.Front()).(P)
		if pos.x == w-1 && pos.y == h-1 {
			break
		}
		if pos.x > 0 && x[pos.y][pos.x-1] == 0 && d[pos.y][pos.x-1] == 0 {
			d[pos.y][pos.x-1] = d[pos.y][pos.x] + 1
			q.PushBack(P{pos.x - 1, pos.y})
		}
		if pos.x < w-1 && x[pos.y][pos.x] == 0 && d[pos.y][pos.x+1] == 0 {
			d[pos.y][pos.x+1] = d[pos.y][pos.x] + 1
			q.PushBack(P{pos.x + 1, pos.y})
		}
		if pos.y > 0 && y[pos.y-1][pos.x] == 0 && d[pos.y-1][pos.x] == 0 {
			d[pos.y-1][pos.x] = d[pos.y][pos.x] + 1
			q.PushBack(P{pos.x, pos.y - 1})
		}
		if pos.y < h-1 && y[pos.y][pos.x] == 0 && d[pos.y+1][pos.x] == 0 {
			d[pos.y+1][pos.x] = d[pos.y][pos.x] + 1
			q.PushBack(P{pos.x, pos.y + 1})
		}
	}
	return d[h-1][w-1]
}

// I/O template
type Io struct {
	reader    *bufio.Reader
	writer    *bufio.Writer
	tokens    []string
	nextToken int
}

func NewIo() *Io {
	return &Io{
		reader: bufio.NewReader(os.Stdin),
		writer: bufio.NewWriter(os.Stdout),
	}
}

func (io *Io) Flush() {
	err := io.writer.Flush()
	if err != nil {
		panic(err)
	}
}

func (io *Io) NextLine() string {
	var buff []byte
	for {
		line, isPrefix, err := io.reader.ReadLine()
		if err != nil {
			panic(err)
		}
		buff = append(buff, line...)
		if !isPrefix {
			break
		}
	}
	return string(buff)
}

func (io *Io) Next() string {
	for io.nextToken >= len(io.tokens) {
		line := io.NextLine()
		io.tokens = strings.Fields(line)
		io.nextToken = 0
	}
	s := io.tokens[io.nextToken]
	io.nextToken++
	return s
}

func (io *Io) NextInt() int {
	i, err := strconv.Atoi(io.Next())
	if err != nil {
		panic(err)
	}
	return i
}

func (io *Io) NextFloat() float64 {
	i, err := strconv.ParseFloat(io.Next(), 64)
	if err != nil {
		panic(err)
	}
	return i
}

func (io *Io) Println(a ...interface{}) {
	fmt.Fprintln(io.writer, a...)
}

func (io *Io) Printf(format string, a ...interface{}) {
	fmt.Fprintf(io.writer, format, a...)
}

func (io *Io) PrintIntSlice(a []int) {
	b := []interface{}{}
	for _, x := range a {
		b = append(b, x)
	}
	io.Println(b...)
}

func (io *Io) PrintStringSlice(a []string) {
	b := []interface{}{}
	for _, x := range a {
		b = append(b, x)
	}
	io.Println(b...)
}

func Log(name string, value interface{}) {
	fmt.Fprintf(os.Stderr, "%s=%+v\n", name, value)
}

func ExampleIo() {
	io := NewIo()
	defer io.Flush()
	a := make([]int, 0, 3)
	a[0], a[1], a[2] = io.NextInt(), io.NextInt(), io.NextInt()
	io.Println(a)
	io.PrintIntSlice(a)
	Log("io", a)
}

Python: # https://atcoder.jp/contests/joi2012yo/tasks/joi2012yo_e

from collections import deque


class Point:
    def __init__(self):
        super().__init__()
        self.up = 1
        self.down = 1
        self.left = 1
        self.right = 1


def solve(W, H):
    Points = {}
    for i in range(H):
        for j in range(W):
            point = Point()
            Points[(i, j)] = point

    for i in range(H * 2 - 1):
        if i % 2 == 0:
            # | | | vertical
            walls = list(map(int, input().split()))
            for j, wall in enumerate(walls):
                Points[(i//2, j)].right = wall
                Points[(i//2, j + 1)].left = wall
        else:
            # - - - horizontal
            walls = list(map(int, input().split()))
            for j, wall in enumerate(walls):
                Points[(i//2, j)].down = wall
                Points[(i//2 + 1, j)].up = wall

    queue = deque()
    queue.appendleft((0, 0, 1))
    checked = set()
    goal = (H-1, W-1)

    result = 0
    while queue:
        # print(queue)
        i, j, d = queue.pop()
        if (i, j) in checked:
            continue
        checked.add((i, j))

        if (i, j) == goal:
            result = d
            break

        point = Points[(i, j)]
        tmp_d = d+1
        if point.up == 0:
            queue.appendleft((i-1, j, tmp_d))
        if point.down == 0:
            queue.appendleft((i+1, j, tmp_d))
        if point.left == 0:
            queue.appendleft((i, j-1, tmp_d))
        if point.right == 0:
            queue.appendleft((i, j+1, tmp_d))

    print(result)


if __name__ == "__main__":
    while True:
        W, H = map(int, input().split())
        if W == 0 and H == 0:
            break

        solve(W, H)

Python: from collections import deque

U = 0
R = 1
D = 2
L = 3
CNT = 4

directions = [[0, 1], [0, -1], [1, 0], [-1, 0]]

while True:
    W, H = map(int, input().split())
    if W == 0 and H == 0:
        break

    maze = [[[1, 1, 1, 1, float('inf')] for _ in range(W)] for _ in range(H)]
    maze[0][0][U] = 0
    maze[0][0][CNT] = 0
    maze[H-1][W-1][D] = 0
    for h in range(H*2-1):
        A = list(map(int, input().split()))
        # 横の壁を取り去る
        if h % 2 == 0:
            for w, a in enumerate(A):
                if a == 0:
                    maze[h//2][w][R] = 0
                    maze[h//2][w+1][L] = 0
        # 縦の壁を取り去る
        else:
            for w, a in enumerate(A):
                if a == 0:
                    maze[h//2][w][D] = 0
                    maze[h//2+1][w][U] = 0

    q = deque([[0, 0]])
    while q:
        y, x = q.popleft()
        for dy, dx in directions:
            if 0 <= y+dy < H and 0 <= x+dx < W:
                if (dy == 1 and maze[y][x][D] == 0) or \
                    (dy == -1 and maze[y][x][U] == 0) or \
                    (dx == 1 and maze[y][x][R] == 0) or \
                    (dx == -1 and maze[y][x][L] == 0):
                    if maze[y+dy][x+dx][CNT] > maze[y][x][CNT] + 1:
                        maze[y+dy][x+dx][CNT] = maze[y][x][CNT] + 1
                        q.append([y+dy, x+dx])

    if maze[H-1][W-1][CNT] == float('inf'):
        print(0)
    else:
        print(maze[H-1][W-1][CNT]+1)

Python: while True:
    w, h = map(int, input().split())
    if w == 0 and h ==0:
        break
    goal = (w,h)
    vart = []
    hori = []
    for i in range(2*h-1):
        if i % 2 == 0:
            vart.append(list(map(int, input().split())))
        else:
            hori.append(list(map(int, input().split())))
    node = [[0 for i in range(h)] for i in range(w)]
    queue = [(0,0,1)]
    res = 0
    while queue:
        p = queue.pop(0)
        x, y, z = p[0], p[1], p[2]
        if x == w-1 and y == h-1:
            res = z
            break
        node[x][y] += 1
        if y-1 >= 0 and hori[y-1][x] == 0 and node[x][y-1] == 0:
            node[x][y-1] = node[x][y]
            queue.append((x,y-1,z+1))
        if y+1 < h and hori[y][x] == 0 and node[x][y+1] == 0:
            node[x][y+1] = node[x][y]
            queue.append((x,y+1,z+1))
        if x-1 >= 0 and vart[y][x-1] == 0 and node[x-1][y] == 0:
            node[x-1][y] = node[x][y]
            queue.append((x-1,y,z+1))
        if x+1 < w and vart[y][x] == 0 and node[x+1][y] == 0:
            node[x+1][y] = node[x][y]
            queue.append((x+1,y,z+1))
    print(res)