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++: #pragma warning(disable:4786) 
#include<stdio.h>
#include<queue>
#include<cstdio>
#include <iostream>
using namespace std;

int main(void){

	int twa[30][30],ywa[30][30], maze[30][30];
	int w,h,dis,ans;
	queue<pair<int,int> > que;
	queue<int> dist;
	pair<int,int> loc;
	while(1){

		scanf("%d %d",&w,&h);
		for(int i=0;i<30;i++){
			for(int j=0;j<30;j++){
				maze[i][j]=0;
			}
		}
		ans=0;
		if(w==0&&h==0) break;
	
		for(int j=0;j<h;j++){
			for(int i=0;i<w-1;i++){
				scanf("%d",&twa[i][j]);
			}
			for(int i=0;i<w;i++){
				if(h-1!=j) scanf("%d",&ywa[i][j]);
			}
		}

		que.push(pair<int,int>(0,0));
		dist.push(1);
		maze[0][0]=1;
		while(que.size()!=0){
			loc=que.front();
			dis=dist.front();
			que.pop();
			dist.pop();
			if(loc.first==w-1&&loc.second==h-1){
				ans=dis;
				break;
			}
			if(loc.first>0){
				if(twa[loc.first-1][loc.second]==0&&maze[loc.first-1][loc.second]==0){
					que.push(pair<int,int>(loc.first-1,loc.second));
					dist.push(dis+1);
					maze[loc.first-1][loc.second]=1;
				}
			}

			if(loc.first<w){
				if(twa[loc.first][loc.second]==0&&maze[loc.first+1][loc.second]==0){
					que.push(pair<int,int>(loc.first+1,loc.second));
					dist.push(dis+1);
					maze[loc.first+1][loc.second]=1;
				}
			}

			if(loc.second>0){
				if(ywa[loc.first][loc.second-1]==0&&maze[loc.first][loc.second-1]==0){
					que.push(pair<int,int>(loc.first,loc.second-1));
					dist.push(dis+1);
					maze[loc.first][loc.second-1]=1;
				}
			}

			if(loc.second<h){
				if(ywa[loc.first][loc.second]==0&&maze[loc.first][loc.second+1]==0){
					que.push(pair<int,int>(loc.first,loc.second+1));
					dist.push(dis+1);
					maze[loc.first][loc.second+1]=1;
				}
			
			}

		}

		printf("%d\n",ans);
	}
	return 0;
}

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

using namespace std;

int main(){
  int w,h;
  char maze[1000][1000];

  cin>>w>>h;
  while(w!=0 && h!=0){
    //  cout<<w<<"::::::"<<h<<endl;
    //入力を元に'#'と'.'からなる迷路を作成
    for(int i=0;i<2*w+1;i++){
      maze[0][i] = '#';
    }
    maze[0][1] = 's';//start

    for(int i=1;i<h*2;i++){
      int c;
      if(i%2 != 0){//縦の壁情報
	maze[i][0] = '#';//最左の壁
	for(int j=1;j<w*2;j++){
	  if(j %2 ==0){
	    cin>>c;
	    if(c==0){
	      maze[i][j] = '.';
	    }else{
	      maze[i][j] = '#';//最右の壁
	    }
	  }else{
	    maze[i][j] = '.';
	  }
	}
	maze[i][w*2] = '#';
      }else{//横の壁情報
	maze[i][0] = '#';
	for(int j=1;j<w*2;j++){
	  if(j%2 == 0){
	    maze[i][j] = '#';
	  }else{
	    cin>>c;
	    if(c==0){
	      maze[i][j] = '.';
	    }else{
	      maze[i][j] = '#';
	    }
	  }

	}
	maze[i][w*2] = '#';
      }
    }
 
    for(int i=0;i<2*w+1;i++){
      maze[h*2][i] = '#';
    }
    maze[h*2][w*2-1] = 'g';//goal

    //debug 
    // for(int i=0;i<h*2+1;i++){
    //   for(int j=0;j<w*2+1;j++){
    // 	cout<<maze[i][j];
    //   }
    //   cout<<endl;
    // }

    int ans = 0;
    int next[4][2] = {{1,0},{-1,0},{0,1},{0,-1}};
    queue<pair<pair<int,int>,int> >  que;
    que.push(make_pair(make_pair(0,1),0));

    while(!que.empty()){

      pair<int,int> now = que.front().first;
      int count = que.front().second;
      que.pop();
    
      if(maze[now.first][now.second] == 'g'){
	ans = count;

	break;
      }
      maze[now.first][now.second] ='#';

      for(int i=0;i<4;i++){
	int ny = now.first + next[i][0];
	int nx = now.second + next[i][1];
	if(ny>=0 && nx>=0 && ny<=h*2 && nx<=w*2 && maze[ny][nx] != '#'){
	  que.push(make_pair(make_pair(ny,nx),count+1));
	}
      }

    }

    cout<<ans/2<<endl;
    cin>>w>>h;
  }

  return 0;
}