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 repd(i,a,b) for (int i=(a);i<(b);i++)
#define rep(i,n) repd(i,0,n)
#define all(x) (x).begin(),(x).end()
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
typedef long long ll;
const long long INF = 1LL << 60;
typedef pair<int, int> P;
int W, H;
int dx[4] = {0, 0, 1, -1};
int dy[4] = {1, -1, 0, 0};
int main()
{
    while (1) {
        cin >> W >> H;
        if (W == 0 && H == 0) break;
        vector<vector<int>> maze(H * 2 + 1, vector<int>(W * 2 + 1, 0));
        rep(i, W * 2 + 1) {
            maze[0][i] = 1; maze[H * 2][i] = 1;
        }
        rep(i, H * 2 + 1) {
            maze[i][0] = 1; maze[i][W * 2] = 1;
        }
        
        rep(i, 2 * H - 1) {
            int k;
            if (i % 2 == 0) {
                rep(j, W - 1) {
                    cin >> k;
                    maze[i + 1][(j + 1) * 2] = k;
                }
            }
            else {
                rep(j, W) {
                    cin >> k;
                    maze[i + 1][j * 2 + 1] = k;
                }
            }
        }

        queue<P> que;
        vector<vector<int>> d(H * 2 + 1, vector<int>(W * 2 + 1, -1));
        que.push(P(1, 1)); //(x, y)
        d[1][1] = 1;
        int gx = W * 2 - 1, gy = H * 2 - 1;
        while (!que.empty()) {
            P p = que.front(); que.pop();
            if (p.first == gx && p.second == gy) break;
            rep(i, 4) {
                int tx = dx[i] + p.first, ty = dy[i] + p.second;
                if (maze[ty][tx] == 1) continue;
                if (d[ty + dy[i]][tx + dx[i]] != -1) continue;
                d[ty + dy[i]][tx + dx[i]] = d[p.second][p.first] + 1;
                que.push(P(tx + dx[i], ty + dy[i]));
            }
        }
        cout << (d[gy][gx] == -1 ? 0 : d[gy][gx]) << endl;


    }

    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

const int INF = 1e+9;
typedef pair<int, int> P;

int dx[] = {1, -1, 0, 0};
int dy[] = {0, 0, -1, 1};
int h, w;
int maze[256][128];

bool check(int x, int y){
	return x >= 0 && x < w && y >= 0 && y < h * 2 - 1 && maze[y][x] == 0;
}
int main() {
	
	while(cin >> w >> h && (w || h)){
		for(int i = 0; i < 256; ++i)
			for(int j = 0; j < 128; ++j)
				maze[i][j] = 0;
			
		for(int i = 0; i < h * 2 - 1; ++i){
			if(i % 2){
				for(int j = 0; j < w; ++j){
					scanf("%d", &maze[i][j]);
				}
			}
			else{
				for(int j = 0; j < w - 1; ++j){
					scanf("%d", &maze[i][j]);
				}		
			}
		}
		int d[128][128];
		for(int i = 0; i < 128; ++i)
			for(int j = 0; j < 128; ++j)
				d[i][j] = INF;
		
		int ans = 0;
		queue<P> que;
		que.push(P(0, 0));
		d[0][0] = 0;
		while(!que.empty()){
			P p = que.front();
			que.pop();
			if(p.first == w - 1 && p.second == h - 1){
				ans = d[h - 1][w - 1] + 1;
				break;
			}
			for(int i = 0; i < 2; ++i){
				int nx = p.first + dx[i];
				int ny = p.second + dy[i];
				if(check(nx - 1, ny * 2) && d[ny][nx] == INF){
					d[ny][nx] = d[p.second][p.first] + 1;
					que.push(P(nx, ny));
				}
			}
			for(int i = 2; i < 4; ++i){
				int nx = p.first + dx[i];
				int ny = p.second + dy[i];
				if(i == 2 && check(nx, ny * 2 + 1) && d[ny][nx] == INF){
					d[ny][nx] = d[p.second][p.first] + 1;
					que.push(P(nx, ny));
				}
				else if(i == 3 && check(nx, ny * 2 - 1) && d[ny][nx] == INF){
					d[ny][nx] = d[p.second][p.first] + 1;
					que.push(P(nx, ny));
				}
			}
		}
		cout << ans << endl;
	}
	
	return 0;
}