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<cstdio>
#include<queue>
#include<iostream>
#include<algorithm>
#include<vector>
#include<string>
#include<set>

using namespace std;

#define reps(i,f,n) for(int i=f;i<int(n);i++)
#define rep(i,n) reps(i,0,n)

class P{
	public:
	int x,y,val;
	P(int x,int y,int val):x(x),y(y),val(val){}
};

int main(){
	
	A:;
	int w,h;
	cin>>w>>h;
	if(w==0 && h==0)return 0;
	
	vector<int> tall[33];
	vector<int> wall[33];
	
	rep(i,h){
		rep(j,w-1){
			int a;
			cin>>a;
			tall[i].push_back(a);
		}
		
		if(i==h-1)continue;
		rep(j,w){
			int a;
			cin>>a;
			wall[i].push_back(a);
		}
	}
	
	queue<P> que;
	que.push(P(0,0,0));
	
	int visit[33][33]={0};
	int ans = 0;
	while(1){
		if(que.empty())break;
		
		P u = que.front();
		que.pop();
		
		int x = u.x;
		int y = u.y;
		int val = u.val;
		
		if(visit[x][y]==1)continue;
		visit[x][y]=1;
		
		if(x==w-1 && y==h-1){
			ans = val;
			break;
		}
		
		if(x<w-1 && tall[y][x]==0)que.push(P(x+1,y,val+1));
		if(x-1>=0 && tall[y][x-1]==0)que.push(P(x-1,y,val+1));
		if(y<h-1 && wall[y][x]==0)que.push(P(x,y+1,val+1));
		if(y-1>=0 && wall[y-1][x]==0)que.push(P(x,y-1,val+1));
	}
	
	if(ans==0)puts("0");
	else printf("%d\n",ans+1);
	
	goto A;
}

C++: #include<iostream>
#include<algorithm>
#include<queue>
using namespace std;
const int dy[] = { 0, 2, 0, -2 };
const int dx[] = { 2, 0, -2, 0 };
static int w;
static int h;
static int map[100][100];
int main()
{
	while (cin >> w >> h && w != 0 || h != 0)
	{
		for (int i = 0; i < 100; i++)
		{
			for (int j = 0; j < 100; j++)
			{
				map[i][j] = 0;
			}
		}

		for (int i = 0; i < h + (h - 1); i++)
		{
			for (int j = (i + 1) % 2; j < w + (w - (i + 1) % 2); j+=2)
			{
				cin >> map[i][j];
			}
		}
		int ans = 0;
		bool path[100][100];
		for (int i = 0; i < h + (h - 1); i++)
		{
			for (int j = 0; j < w + (w - 1); j++)
			{
				path[i][j] = false;
			}
		}
		queue<pair<pair<int,int>,int> >q;
		q.push(make_pair(make_pair(0, 0), 1));
		while (q.size() > 0)
		{
			pair<pair<int,int>,int> p = q.front();
			q.pop();
			path[p.first.second][p.first.first] = true;
			if (p.first.first == w + (w - 1) - 1 && p.first.second == h + (h - 1) - 1)
			{
				ans = p.second;
				break;
			}
			for (int i = 0; i < 4; i++)
			{
				int nx = p.first.first + dx[i];
				int ny = p.first.second + dy[i];
				if (nx < 0 || nx >= w + (w - 1))continue;
				if (ny < 0 || ny >= h + (h - 1))continue;
				if (map[ny][nx] == 1)continue;
				if (path[ny][nx])continue;
				int nny = p.first.second + dy[i] / 2;
				int nnx = p.first.first + dx[i] / 2;
				if (nny < 0 || nny >= h + (h - 1))continue;
				if (nnx < 0 || nnx >= w + (w - 1))continue;
				if (map[nny][nnx] == 1)continue;
				q.push(make_pair(make_pair(nx,ny),p.second + 1));
			}
		}

		cout << ans << endl;


	}
	return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<queue>
#include<cstring>
using namespace std;
int main()
{
	int w,h;
	while(scanf(" %d %d",&w,&h),w) 
	{
		int W[2*h][w];
		int H[2*h][w];

		for(int i = 0; i < 2*h-1; ++i)
		{
			for(int j = 0; j < (i%2==0?w-1:w); ++j)
			{
				//cout<<"i="<<i<<",j="<<j<<endl;
				if(i%2==0)
				{
					scanf(" %d",&W[i/2][j]);
					//cout<<"input="<<W[i/2][j]<<endl;
					//cout<<"y="<<i/2<<",x="<<j<<endl;
				}
				else
				{
					scanf(" %d",&H[i/2][j]);
					//cout<<"input="<<W[i/2][j]<<endl;
					//cout<<"y="<<i/2<<",x="<<j<<endl;
				}
			}
		}
		/*cout<<"*************"<<endl;
		for(int i = 0; i < h; ++i)
		{
			for(int j = 0; j < w-1; ++j)
			{
				cout<<" "<<W[i][j];
			}
			cout<<endl;
		}
		cout<<"*************"<<endl;
		for(int i = 0; i < h-1; ++i)
		{
			for(int j = 0; j < w; ++j)
			{
				cout<<" "<<H[i][j];
			}
			cout<<endl;
		}
		*/
		queue<int> xs,ys,steps;
		xs.push(0); ys.push(0); steps.push(1);
		bool used[h][w];
		memset(used,0,sizeof(used));
		int ans=0;
		int dx[4]={1,0,-1,0},dy[4]={0,1,0,-1};
		while(!xs.empty()) 
		{
			int x=xs.front(),y=ys.front(),step=steps.front();
			xs.pop(); ys.pop(); steps.pop();
			//cout<<"x="<<x<<",y="<<y<<endl;
			used[y][x]=true;
			if(y==h-1&&x==w-1)
			{
				ans=step;
				break;
			}
			for(int i = 0; i < 4; ++i)
			{
				int nx=x+dx[i],ny=y+dy[i];
				if(0<=nx&&nx<w&&0<=ny&&ny<h&&!used[ny][nx])
				{
					if( (i==0&&!W[y][x])|| (i==1&&!H[y][x]) || (i==2&&!W[y][nx]) || (i==3&&!H[ny][x]))
					{
						xs.push(nx); ys.push(ny); steps.push(step+1);
					}
				}
			}
		}
		cout<<ans<<endl;
	}
  return 0;
}