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: from collections import deque

def bfs(maze, visited, sy, sx, gy, gx):
    queue = deque([[sy, sx]])
    visited[sy][sx] = 0
    dist = [[0 for _ in range(w)] for _ in range(h)]
    dist[0][0] = 1

    while queue:
        y, x = queue.popleft()
        if [y, x] == [gy, gx]:
            return visited[y][x]
        if x == w-1 and y == h-1:
            break
        for j, k in ([1, 0], [-1, 0], [0, 1], [0, -1]):
            new_y, new_x = y+j, x+k
            block = 0
            if new_x < 0 or new_y < 0 or w <= new_x or h <= new_y:
                continue  

            if j == 1: block = horizontal[y][x]
            if j == -1: block = horizontal[y-1][x]
            if k == 1: block = vertical[y][x]
            if k == -1: block = vertical[y][x-1]

            if block == 0 and \
                visited[new_y][new_x] == -1:
                visited[new_y][new_x] = visited[y][x] + 1
                queue.append([new_y, new_x])
                dist[new_y][new_x] = dist[y][x]+1
    return dist[h-1][w-1]

while True:
    w, h = map(int, input().split())
    if w == 0 : break
    
    vertical = []
    horizontal = []
    
    vertical.append(list(map(int, input().split())))
    for i in range(h-1):
        horizontal.append(list(map(int, input().split())))
        vertical.append(list(map(int, input().split())))
    
    
    maze = [[0]*w for i in range(h)]
    visited = [[-1]*w for j in range(h)]
    print(bfs(maze, visited, 0, 0, h, w))

Python: from collections import deque

while True:
    w, h = map(int, input().split())
    if w == h == 0:
        break
    li = [list(map(int, input().split())) for _ in range(2*h-1)]
    
    Map = [['x'] * (w*2+1)]
    Map += [['x'] + ['.'] * (w*2-1) + ['x'] for _ in range(2*h-1)]
    Map += [['x'] * (w*2+1)]
    
    for i in range(2*h+1):
        for j in range(2*w+1):
            if i%2 == 0 and j%2 == 0:
                Map[i][j] = 'x'
    
    for k in range(2*h-1):
        if k%2 == 0:
            for i in range(len(li[k])):
                if li[k][i] == 1:
                    Map[k+1][i*2+2] = 'x'
        else:
            for i in range(len(li[k])):
                if li[k][i] == 1:
                    Map[k+1][i*2+1] = 'x'
    
    moved = [[0, 1], [0, -1], [1, 0], [-1, 0]]
    stack = deque([(1,1)])
    Map[1][1] = 1
    while stack:
        x, y = stack.popleft()
        for s, t in moved:
            if Map[x+s][y+t] == '.':
                stack.append((x+s, y+t))
                if (x+s) % 2 == 0 or (y+t) % 2 == 0:
                    Map[x+s][y+t] = Map[x][y]
                else:
                    Map[x+s][y+t] = Map[x][y] + 1
    
    ans = Map[2*h-1][-2]
    if ans == '.':
        print(0)
    else:
        print(ans)

Python: # coding: utf-8
import queue
while 1:
    w,h=map(int,input().split())
    if w==0:
        break
    field=[[0 for i in range(w*2-1)] for i in range(h*2-1)]
    dist=[[0 for i in range(w*2-1)] for i in range(h*2-1)]
    for i in range(h*2-1):
        if i%2==0:
            s=input().split()
            for j in range(len(s)):
                if s[j]=='1':
                    field[i][1+j*2]=1
    
        else:
            s=input().split()
            for j in range(len(s)):
                if s[j]=='1':
                    field[i][j*2]=1
    s=(0,0)
    g=(h*2-2,w*2-2)
    q=queue.Queue()
    q.put(s)
    while not q.empty():
        y,x=q.get()
        if g==(y,x):
            print(dist[g[0]][g[1]]+1)
            break
        if 0<=y+1<h*2-1 and 0<=x<w*2-1 and field[y+1][x]!=1 and dist[y+2][x]==0:
            dist[y+2][x]=dist[y][x]+1
            q.put((y+2,x))
        if 0<=y-1<h*2-1 and 0<=x<w*2-1 and field[y-1][x]!=1 and dist[y-2][x]==0:
            dist[y-2][x]=dist[y][x]+1
            q.put((y-2,x))
        if 0<=y<h*2-1 and 0<=x+1<w*2-1 and field[y][x+1]!=1 and dist[y][x+2]==0:
            dist[y][x+2]=dist[y][x]+1
            q.put((y,x+2))
        if 0<=y<h*2-1 and 0<=x-1<w*2-1 and field[y][x-1]!=1 and dist[y][x-2]==0:
            dist[y][x-2]=dist[y][x]+1
            q.put((y,x-2))
    else:
        print(0)