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++: //12:25 13:24 13:30
#include <iostream>
#include <string>
#include <map>
#include <vector>
#include <algorithm>
#include <stack>
#include <queue>

using namespace std;

#define REP(i,k,n) for(int i=k;i<n;i++)
#define rep(i,n) for(int i=0;i<n;i++)
#define INF 1<<30
#define mp make_pair
#define pb pushback

typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int,int> pii;
typedef vector<pair<int,int> > vp;

typedef long long ll;

int dx[4] = {1, 0, 0, 0};
int dy[4] = {1, 2, 1, 0};
int mx[4] = {1, 0, -1, 0};
int my[4] = {0, 1, 0, -1};
int ss[80][40];



int main() {

    while(1){
        int w,h;
        int ss[80][40];
        cin >> w >> h;
        if(w==0)break;
        rep(j,h*2){
            rep(i,w){
                if(j==0){
                    rep(s,w){
                        ss[0][s] = 1;
                        ss[h*2][s] = 1;
                    }
                    continue;
                }
                if(j%2==1){
                    if(i==0){
                        ss[j][0] = 1;
                        ss[j][w] = 1;
                        continue;
                    }
                }
                cin >> ss[j][i];

            }
        }
        /*
        cout << "debug roop " << endl;
        rep(j,h*2+1){
            if(j%2==0){
                cout << " ";
            }
            rep(i,w+1){
                if(j%2==0){
                    if(i==w){
                        break;
                    }
                }
                cout << ss[j][i] << " ";
            }
            cout << endl;
        }*/
        //??????????????¢?´¢
        
        queue<int> x;
        queue<int> y;
        queue<int> res;
        x.push(0);
        y.push(0);
        res.push(0);
        int resres;
        while(1){
            int xx = x.front();
            int yy = y.front();
            resres = res.front();
            // cout << "debug xx,yy"<<xx<<","<<yy<<endl;
            x.pop();
            y.pop();
            res.pop();
            if(xx==w-1 && yy==h-1){
                break;
            }
            //dsaw
            rep(i,4){
                // cout<<"de:"<<ss[yy*2+dy[i]][xx+dx[i]]<<endl;
                if(ss[yy*2+dy[i]][xx+dx[i]] == 0){
                    x.push(xx+mx[i]);
                    y.push(yy+my[i]);
                    res.push(resres+1);
                    ss[yy*2+dy[i]][xx+dx[i]] = 1;
                };
            }
            if(x.empty()==1){
                resres = -1;
                break;
            }
        }
        cout << resres+1 << endl;
    }



    return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <cctype>
#include <cstdio>
#include <math.h>
#include <map>
#include <queue>
#include <string>
using namespace std;

int w,h,V[30][31],H[31][30],field[30][31];
int sx,sy,gx,gy,d[30][30],dx[4]={1,0,-1,0},dy[4]={0,1,0,-1};
const int INF=9999999;
typedef pair<int,int> P;

int bfs(){
    queue<P> que;
    for(int i=0;i<h;i++){
	for(int j=0;j<w;j++)d[i][j]=INF;
    }
    que.push(P(sy,sx));
    d[sx][sy]=0;
    while(que.size()){
	P p=que.front(); que.pop();
	if(p.first==gx&&p.second==gy)break;
	for(int i=0;i<4;i++){
	    int nx=p.first+dx[i],ny=p.second+dy[i];
	    if(0<=nx&&nx<h&&0<=ny&&ny<w&&d[nx][ny]==INF&&(i==0&&H[nx][ny+1]==0||i==1&&V[nx+1][ny]==0||i==2&&H[nx+1][ny+1]==0||i==3&&V[nx+1][ny+1]==0)){
		que.push(P(nx,ny));
		d[nx][ny]=d[p.first][p.second]+1;
	    }
	}
    }
    return d[gx][gy];
}

int main() {
    while(cin>>w>>h){
    	if(w+h==0)return 0;
    	for(int i=0;i<h;i++){
    		for(int j=0;j<w-1;j++)cin>>V[i+1][j+1];
    		if(i!=h-1)for(int j=0;j<w;j++)cin>>H[i+1][j+1];
    	}
    	sx=0;sy=0;gx=h-1;gy=w-1;
    	if(bfs()==INF)cout<<0<<endl;
    	else cout<<bfs()+1<<endl;
    }
}