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 <queue>
using namespace std;

typedef struct _info{
    int x;
    int y;
    int s;
    _info(int xx, int yy, int ss){
        x=xx; y=yy; s=ss;
    }
} info;

int dx[4]={1,-1,0,0};
int dy[4]={0,0,1,-1};

bool cango(int x1, int y1, int x2, int y2,
           vector<vector<bool> >& hwall, vector<vector<bool> >&wwall){
    if(x2<x1) swap(x1,x2);
    if(y2<y1) swap(y1,y2);
    if(x1<0 || y1<0) return false;
    if(x1==x2){
        return hwall[y1][x1];
    }else{
        return wwall[y1][x1];
    }
}

int main(){
    while(1){
        int w,h;
        cin >> w >> h;
        if(w==0) break;

        vector<vector<bool> > map(h, vector<bool>(w, true));
        vector<vector<bool> > hwall(h, vector<bool>(w, false));
        vector<vector<bool> > wwall(h, vector<bool>(w, false));
        for(int i=0; i<h; i++){
            int tmp;
            for(int j=0; j<w-1; j++){
                cin >> tmp;
                if(tmp==0) wwall[i][j]=true;
            }
            if(i==h-1) break;
            for(int j=0; j<w; j++){
                cin >> tmp;
                if(tmp==0) hwall[i][j]=true;
            }
        }

        int gx=w-1;
        int gy=h-1;
        queue<info> search;
        info start(0,0,1);
        search.push(start);
        map[0][0]=false;
        bool find=false;
        while(!search.empty()){
            info cur = search.front();
            search.pop();
            if(cur.x==gx && cur.y==gy){
                cout << cur.s << endl;
                find = true;
                break;
            }

            for(int i=0; i<4; i++){
                int nx=cur.x+dx[i];
                int ny=cur.y+dy[i];
                if(cango(cur.x, cur.y, nx, ny, hwall, wwall) && map[ny][nx]){
                    info next(nx,ny,cur.s+1);
                    search.push(next);
                    map[ny][nx] = false;
                }
            }
        }
        if(!find){
            cout << 0 << endl;
        }
    }
    return 0;
}

C++: #include <iostream>
#include <string>
#include <sstream>
#include <algorithm>
#include <vector>
#include <utility>
#include <functional>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <deque>
#include <ctime>
 
using namespace std;


 
#define rep(i,n) REP(i,0,n)
#define REP(i,s,e) for(int i=(s); i<(int)(e); i++)
#define pb push_back
#define mp make_pair
#define all(r) r.begin(),r.end()
#define fi first
#define se second
#define println(X) cout<<X<<endl;
#define DBG(X) cout<<#X<<" : "<<X<<endl;
 

 
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vii;
typedef vector<ll> vl;
typedef vector<vl> vll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;



const int INF = 1e9;
const ll MOD = 1e9 + 7;
double EPS = 1e-7;


//LURD
int dx[]={-1,0,1,0};
int dy[]={0,-1,0,1};

int d[110][110][4];
int used[110][110];

int x, y, nx, ny, c;

int main(){
	int h, w, t;
	while(cin>>w>>h){
		//cout<<h<<" "<<w<<endl;
		if(h == 0 && w == 0) break;
		for(int i = 0; i < 110; i++){
			for(int j = 0; j < 110; j++){
				for(int k = 0; k < 4; k++){
					d[i][j][k] = 1;
				}
				used[i][j] = 0;
			}
		}
		for(int i = 0; i < 2 * h -1; i++){
			if(i % 2 == 0){
				for(int j = 0; j < w-1; j++){
					cin>>t;
					if(t == 0){
						d[i/2+1][j+1][2] = 0;
						d[i/2+1][j+2][0] = 0;
					}
				}
			}
			else{
				for(int j = 0; j < w; j++){
					cin>>t;
					if(t == 0){
						d[i/2+1][j+1][3] = 0;
						d[i/2+2][j+1][1] = 0;
					}
				}
			}
		}
		// for(int i = 1; i <= h; i++){
		// 	for(int j = 1; j <= w; j++){
		// 		cout<<" "<<d[i][j][1];
		// 	}
		// 	cout<<endl;
		// }
		queue<pair<int, pii> > q;
		pair<int, pii> p(mp(0,mp(1,1)));
		used[1][1] = 1;
		q.push(p);
		int ans = -1;
		while(!q.empty()){
			p = q.front(); q.pop();
			c = p.fi;
			x = p.se.se; y = p.se.fi;
			//cout<<x<<" "<<y<<" "<<c<<endl;
			for(int i = 0; i < 4; i++){
				nx = x + dx[i];
				ny = y + dy[i];
				if(d[y][x][i]==1 || used[ny][nx] == 1) continue;
				if(nx == w && ny == h){
					ans = c + 1;
					while(!q.empty()) q.pop();
					break;
				}
				q.push(mp(c+1, mp(ny, nx)));
				used[ny][nx] = 1;
			}
		}
		cout<<ans+1<<endl;
	}
}