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)
}

C++: #include<iostream>
#include<queue>
#include<utility>
using namespace std;

typedef pair<int,int> P;

int main(){
  int w,h;
  bool vw[50][50],pw[50][50];
  int grid[50][50];

  while(cin >> w >>h , w||h){
    for(int i=0;i<h;i++){
      for(int j=0;j<w-1;j++)cin >> vw[i][j];
      if(i!=h-1)for(int j=0;j<w;j++)cin >> pw[i][j];
    }

    for(int i=0;i<h;i++)
      for(int j=0;j<w;j++)grid[i][j] = 0;
    
    grid[0][0] = 1;
    queue<P> q;
    q.push(P(0,0));

    while(q.size()){
      P p = q.front(); q.pop();
      int y = p.first, x = p.second;

      if(y==h-1 && x==w-1)break;

      if(0<=y-1 && !pw[y-1][x] && !grid[y-1][x]){
	grid[y-1][x] = grid[y][x]+1;
	q.push(P(y-1,x));
      }
      if(0<=x-1 && !vw[y][x-1] && !grid[y][x-1]){
	grid[y][x-1] = grid[y][x]+1;
	q.push(P(y,x-1));
      }
      if(y+1<h && !pw[y][x] && !grid[y+1][x]){
	grid[y+1][x] = grid[y][x]+1;
	q.push(P(y+1,x));
      }
      if(x+1<w && !vw[y][x] && !grid[y][x+1]){
	grid[y][x+1] = grid[y][x]+1;
	q.push(P(y,x+1));
      }
    }
    cout << grid[h-1][w-1] << endl;
  }
}

C++: #include <iostream>
#include <vector>
#include <algorithm>
#include <queue>


bool	OK(std::pair<int, int> &next, std::pair<int, int>& now, std::vector<std::vector<int> >& w_x, std::vector<std::vector<int> >& w_y, int dx, int dy)
{
	if (dy < 0)
	{
		if (w_y[next.first][next.second] == 1)
			return (false);
	}
	if (dy > 0)
	{
		if (w_y[now.first][now.second] == 1)
			return (false);
	}
	if (dx < 0)
	{
		if (w_x[next.first][next.second] == 1)
			return (false);
	}
	if (dx > 0)
	{
		if (w_x[now.first][now.second] == 1)
			return (false);
	}
	return (true);
}

void	bfs(std::queue<std::pair<int, int> >& Que, std::vector<std::vector<int> >&map, std::vector<std::vector<int> >& w_x, std::vector<std::vector<int> >& w_y, int w, int h)
{
	int dx[] = {1, 0, -1, 0};
	int dy[] = {0, 1, 0, -1};
	while (!(Que.empty()))
	{
		std::pair<int, int> now = Que.front();
		Que.pop();
		for (int i = 0; i < 4; i++)
		{
			std::pair<int, int> next = std::make_pair(now.first + dy[i], now.second + dx[i]);
			if (next.first >= 0 && next.first < h && next.second >= 0 && next.second < w && map[next.first][next.second] == -1 && OK(next, now, w_x, w_y, dx[i], dy[i]))
			{
				map[next.first][next.second] = map[now.first][now.second] + 1;
				Que.push(next);
			}
		}
	}
}

int main()
{
	std::vector<int> ans;
	while (true)
	{
		int w, h;
		std::cin >> w >> h;
		if (!w && !h)
			break ;
		std::vector<std::vector<int> > w_x(31, std::vector<int> (31, -1));
		std::vector<std::vector<int> > w_y(31, std::vector<int> (31, -1));
		std::vector<std::vector<int> > map(31, std::vector<int> (31, -1));
		std::queue<std::pair<int, int> > Que;
		for (int i = 0; i < 2 * h - 1; i++)
		{
			if (i % 2 == 0)
			{
				for (int j = 0; j < w - 1; j++)
					std::cin >> w_x[i / 2][j];//w[x][y] == 1なら、x, yの右に壁があるということ
			}
			else
			{
				for (int j = 0; j < w; j++)
					std::cin >> w_y[i / 2][j];//w[x][y] == 1なら、x, yの下に壁があるということ
			}
		}
		map[0][0] = 1;
		Que.push(std::make_pair(0, 0));
		bfs(Que, map, w_x, w_y, w, h);
		if (map[h - 1][w - 1] == -1)
			ans.push_back(0);
		else
			ans.push_back(map[h - 1][w - 1]);
	}
	for (std::vector<int>::iterator i = ans.begin(); i != ans.end(); i++)
	{
		std::cout << *i << '\n';
	}
	return (0);
}