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 <vector>
#include <algorithm>
#include <string.h>
#include <queue>
using namespace std;
typedef pair<int,int> pa;
typedef pair<int,pair<int,int> > pip;

queue<pip> q;
int maze[170][172];
int visited[170][172];

int main(){
    int w,h,suc=0;
    while(1){
        while (!q.empty())
            q.pop();
        cin>>w>>h;
        if(w==0)break;
        memset(maze,0,sizeof(maze));
        memset(visited,0,sizeof(visited));
        
        for(int i=0;i<2*h+1;i++){
            maze[i][0]=1; maze[i][2*w]=1;
        }
        for(int i=0;i<2*w+1;i++){
            maze[0][i]=1; maze[2*h][i]=1;
        }
        for(int i=1;i<h*2;i++){
            if(i%2==1)
                for(int j=1;j<w;j++)
                    cin>>maze[i][2*j];
            else
                for(int j=1;j<w+1;j++)
                    cin>>maze[i][2*j-1];
        }
        q.push(pip(1,pa(1,1)));
        while(q.size()>0){
            pip tem=q.front(); q.pop(); int f=tem.first; pa p=tem.second;
            int x=p.first,y=p.second;
            if(x==2*w-1&&y==2*h-1){
                cout<<f<<endl;
                suc=1;
                break;
            }
            maze[y][x]=8;
            if(maze[y][x-1]==0&&visited[y][x-2]==0&&x-2>=0){
                q.push(pip(f+1,pa(x-2,y)));
                visited[y][x-2]=1;
            }
            if(maze[y][x+1]==0&&visited[y][x+2]==0&&w+2<=w*2+2){
                q.push(pip(f+1,pa(x+2,y)));
                visited[y][x+2]=1;
            }
            if(maze[y-1][x]==0&&visited[y-2][x]==0&&y-2>=0){
                q.push(pip(f+1,pa(x,y-2)));
                visited[y-2][x]=1;
            }
            if(maze[y+1][x]==0&&visited[y+2][x]==0&&y+2<=h*2+2){
                q.push(pip(f+1,pa(x,y+2)));
                visited[y+2][x]=1;
            }
        }
        if(suc==0)
            cout<<0<<endl;
    }
    return 0;
}

C++: #include<cstdio>
#include<queue>
using namespace std;
typedef pair<int, int> P;
typedef pair<P, int> PP;
static const int MAX_W = 33;
static const int MAX_H = 33;
 
int w, h;
bool field1[MAX_H][MAX_W], field2[MAX_H][MAX_W];
bool visited[MAX_H][MAX_W];
int dy[] = {0, -1, 0, 1};
int dx[] = {1, 0, -1, 0};
 
int bfs(int y, int x){
    fill(visited[0], visited[h], false);
    queue<PP> qa;
    qa.push(PP(P(y, x), 1));
    visited[y][x] = true;
    while(!qa.empty()){
        PP cur = qa.front(); qa.pop();
        int cy = cur.first.first, cx = cur.first.second;
        int dist = cur.second;
        if(cy == h - 1 && cx == w - 1) return dist;
        for(int i = 0; i < 4; i++){
            int ny = cy + dy[i], nx = cx + dx[i];
            if(ny < 0 || ny >= h || nx < 0 || nx >= w) continue;
            if(visited[ny][nx]) continue;
            if(i == 0){
                if(field1[cy][cx]) continue;
            }else if(i == 1){
                if(field2[ny][nx]) continue;
            }else if(i == 2){
                if(field1[ny][nx]) continue;
            }else{
                if(field2[cy][cx]) continue;
            }
            qa.push(PP(P(ny, nx), dist + 1));
            visited[ny][nx] = true;
        }
    }
    return 0;
}
 
int main(){
    for(;;){
        scanf("%d %d", &w, &h);
        if(w == 0 && h == 0) break;
        for(int i = 0; i < 2 * h - 1; i++){
            if(i % 2 == 0){
                for(int j = 0; j < w - 1; j++) scanf("%d", &field1[i / 2][j]);
            }else{
                for(int j = 0; j < w; j++) scanf("%d", &field2[i / 2][j]);
            }
        }
        printf("%d\n", bfs(0, 0));
    }
    return 0;
}