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<bits/stdc++.h>
using namespace std;
#define INF 1000000
//aizu 200???

//??±???????????¢?´¢??§??????????????????

int di[4] = {0, 1, 0, -1};
int dj[4] = {1, 0, -1, 0};

void dfs(int si, int sj, int gi, int gj, int& ans, vector<vector<bool> >& canGo, int counter){


    //??´???????????????ans?????´??°??????return
    if(si == gi && sj == gj){
        ans = min(ans, counter);
        return;
    }

    //???????????¨???????????¢?´¢?????????
    canGo[si][sj] = true;

    //??±???????????¢?´¢??????
    for(int k = 0; k < 4; k++){
        if(canGo[si + di[k]][sj + dj[k]] == 0){
            if(canGo[si + di[k]*2][sj + dj[k]*2] == 0){
                dfs(si + di[k]*2, sj + dj[k]*2, gi, gj, ans, canGo, counter + 1);
            }
        }
    }


    //???????????¨?????????????¨???????
    canGo[si][sj] = false;
    
}

int main(){
    int w, h; cin >> w >> h;
    vector<vector<bool> > canGo(2*h + 2, vector<bool> (2*w + 2, true));
    for(int i = 1; i <= 2*h - 1; i++){
        for(int j = 1; j <= 2*w - 1; j++){
            canGo[i][j] = false;
        }
    }

    //??\???
    for(int i = 1; i <= 2*h - 1; i++){
        if(i % 2 == 1){
            for(int j = 2; j <= 2*w - 1; j += 2){
                bool input; cin >> input;
                canGo[i][j] = input;
            }
        }else{
            for(int j = 1; j <= 2*w - 1; j+= 2){
                bool input; cin >> input;
                canGo[i][j] = input;
            }
        }
    }

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

    int ans = INF;

    dfs(1, 1, 2*h-1, 2*w-1, ans, canGo, 0);

    if(ans != INF) cout << ans + 1 << endl;
    else cout << 0 << endl;
    return 0;

}

C++: #include<cstdio>
#include<algorithm>
#include<iostream>
#include<vector>
#include<string>
#include<queue>
#include<map>

using namespace std;

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

typedef vector<int> vi;
typedef vector<vi> vii;
typedef pair<int,int> pii;

class T{
	public:
	int x,y,ans;
	T(int x,int y,int ans):x(x),y(y),ans(ans){}
};

int main(){
	int w,h;
	A:cin>>w>>h;
	if(w==0)return 0;
	
	int t[31][31]={0};
	int z[31][31]={0};
	rep(i,h){
		rep(j,w-1){
			cin>>t[j][i];
		}
		if(i!=h-1)rep(j,w){
			cin>>z[j][i];
		}
	}
	
	/*
	rep(i,h){
		rep(j,w)printf("%d ",t[i][j]);puts("");
		rep(j,w)printf("%d ",y[i][j]);puts("");
		puts("");
	}*/
	
	queue<T> que;
	que.push(T(0,0,0));
	
	int visit[31][31]={0};
	int ans = -1;
	
	while(1){
		if(que.empty())break;
		
		T u = que.front();
		que.pop();
		
		if(visit[u.x][u.y]==1)continue;
		visit[u.x][u.y]=1;
		
		if(u.x==w-1 && u.y==h-1){
			ans = u.ans;
			break;
		}
		
		int x = u.x;
		int y = u.y;
		if(x<w-1 && t[x][y]!=1)que.push(T(x+1,y,u.ans+1));
		if(y<h-1 && z[x][y]!=1)que.push(T(x,y+1,u.ans+1));
		if(x>0 && t[x-1][y]!=1)que.push(T(x-1,y,u.ans+1));
		if(y>0 && z[x][y-1]!=1)que.push(T(x,y-1,u.ans+1));
	}
	
	printf("%d\n",ans+1);
	
	goto A;
}

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

#define rep(i,n) for(int i=0;i<(n);i++)
#define fr first
#define sc second
int dy[]={1,0,-1,0};
int dx[]={0,1,0,-1};

using namespace std;
typedef pair<int,int> P;
int W,H;
string maze[100];
const int INF=1e9;

void solve() {
    int dp[100][100];
    rep(y,100) rep(x,100) dp[y][x]=INF;
    getchar();
    rep(y,2*H-1) getline(cin,maze[y]);
    rep(y,2*H-1) {
        if(y%2==0) {
            maze[y][maze[y].size()-1]=' ';
        }
    }
    queue<P> que;
    que.push(P(0,0));
    dp[0][0]=0;
    while(que.size()) {
        P p=que.front(); que.pop();
        rep(k,4) {
            int ny=p.fr+dy[k];
            int nx=p.sc+dx[k];
            int ny2=ny+dy[k];
            int nx2=nx+dx[k];
            if(!(0<=ny&&ny<2*H-1)) continue;
            if(!(0<=nx&&nx<2*W-1)) continue;
            if(!(0<=ny2&&ny2<2*H-1)) continue;
            if(!(0<=nx2&&nx2<2*W-1)) continue;
            if(dp[ny2][nx2]!=INF) continue;
            if(maze[ny][nx]=='1') continue;

            //printf("(%d, %d) -> (%d, %d)\n",p.fr,p.sc,ny2,nx2);
            dp[ny2][nx2]=dp[p.fr][p.sc]+1;
            que.push(P(ny2,nx2));
        }
    }

    int ans=dp[2*H-2][2*W-2];
    if(ans==INF) ans=0;
    else ans++;
    cout<<ans<<endl;
}

int main() {
    while(cin>>W>>H) {
        if(!W) break;
        solve();
    }
    return 0;
}