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 <bits/stdc++.h>

using namespace std;

bool valid(int y, int x)
{
    return (y >= 0 && x >= 0);
}

int main()
{
    int w, h;
    int dy[4] = {0, 1, 0, -1};
    int dx[4] = {1, 0, -1, 0};
    
    while (scanf("%d %d", &w, &h) && w){
        bool wall[128][128] = {0};
        int step[128][128];
        
        for (int i = 0; i < 128; i++){
            fill(step[i], step[i] + 128, 999);
        }
        
        fill(wall[0], wall[0] + 128, 1);
        wall[0][1] = 0;
        fill(wall[h * 2], wall[h * 2] + 128, 1);
        wall[h * 2][2 * w - 1] = 0;
        for (int i = 1; i <= h * 2 - 1; i++){
            if (i % 2 == 0){
                for (int j = 0; j < w; j++){
                    int x;
                    wall[i][2 * j] = 1;
                    scanf("%d", &x);
                    wall[i][2 * j + 1] = x;
                }
                wall[i][2 * w] = 1;
            }
            else {
                wall[i][0] = wall[i][2 * w] = true;
                for (int j = 2; j <= 2 * (w - 1); j += 2){
                    int x;
                    scanf("%d", &x);
                    wall[i][j] = x;
                }
            }
        }
        
        queue<pair<int, int> > q;
        step[0][1] = 0;
        for (q.push(make_pair(0, 1)); q.size(); q.pop()){
            pair<int, int> pos = q.front();
            
            for (int i = 0; i < 4; i++){
                pair<int, int> npos = make_pair(pos.first + dy[i], pos.second + dx[i]);
                
                if (valid(npos.first, npos.second) && step[npos.first][npos.second] == 999 && !wall[npos.first][npos.second]){
                    step[npos.first][npos.second] = step[pos.first][pos.second] + ((pos.first & 1) & (pos.second & 1));
                    q.push(npos);
                }
            }
        }
        
        printf("%d\n", step[h * 2][w * 2 - 1] == 999 ? 0 : step[h * 2][w * 2 - 1]);
    }
    
    return (0);
}

C++: #include<iostream>
#include<cstdio>
#include<string>
#include<queue>

using namespace std;
int bfs(int x,int y);
int w,h;
int i,j;
int dy[4] = {1,0,-1,0}, dx[4] = {0,-1,0,1};
string map[100];
int dis[100][100];
queue<pair<int,int> > q;
int main(){
  while(1){
    cin >> w >> h;
    if(w == 0 && h == 0) break;
    w = 2*w -1;
    h = 2*h -1;
    cin.ignore();
    for(i = 0;i < h;i++){
      getline(cin,map[i]);
    }
    bfs(0,0);
    //cout << dis[4][2] +1<<endl;
    if(dis[h-1][w-1] > 0){
    cout << dis[h-1][w-1] +1<<endl;
    }else{
      cout << 0 <<endl;
    }
  }
  return 0;
}

int bfs(int x,int y){
  int k;
  //cout << "x = "<<x<<endl;
  //cout << "y = "<<y<<endl;
  pair<int,int> tmp;
  for(k = 0;k < 4;k++){
    if(y +  2*dy[k] >-1 && y + 2*dy[k] < h && x + 2*dx[k] < w && x + 2*dx[k] > -1){
      // cout << "dx = "<<dx[k]<<endl;
      //cout << "dy = "<<dy[k]<<endl;
      if(map[y + dy[k]][x + dx[k]] == '0'){
	map[y + dy[k]][x + dx[k]] ='1';
	tmp.second = x + 2*dx[k];
	tmp.first = y +2*dy[k];
	q.push(tmp);
	dis[y + 2*dy[k]][x + 2*dx[k]] = dis[y][x] + 1;
	//cout << dis[y + 2*dy[k]][x + 2*dx[k]]<<endl;
      }
    }
  }
  while(q.size() != 0){
    tmp = q.front();
    q.pop();
    bfs(tmp.second,tmp.first);
  }
  return 0;
}