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>

#define FOR(i, a, b) for(long long int i=(a);i<=(b);i++)
#define RFOR(i, a, b) for(long long int i=(a);i>=(b);i--)
#define MOD 1000000007
#define INF 1000000000 //2000000000
#define LLINF 1000000000000000000 //9000000000000000000
#define PI 3.14159265358979

using namespace std;
typedef long long int ll;
typedef pair< long long int, long long  int> P;


int main(void) {
	
	while (1) {
		int h, w;
		int wall;
		bool flag = true;
		bool check = false;
		int dp[65][65] = {};
		class Pos {
		public:
			int xx;
			int yy;
			int deep = 0;
			bool chcked = false;
		};
		Pos pos[65][65] = {};
		Pos now;
		queue<Pos> que;

		cin >> w >> h;
		FOR(i, 0, 64) {
			FOR(t, 0, 64) {
				pos[i][t].xx = t;
				pos[i][t].yy = i;
			}
		}
		FOR(i, 0, 2*h) {
			dp[i][0] = 1;
			dp[i][2*w] = 1;
		}
		FOR(i, 0, 2*w) {
			dp[0][i] = 1;
			dp[2*h][i] = 1;
		}

		if (w == 0) {
			break;
		}
		FOR(i, 1, 2 * h - 1) {
			if (flag) {
				FOR(j, 1, w - 1) {
					cin >> wall;
					if (wall == 1) {
						dp[i][j * 2] = 1;
					}
				}
				flag = false;
			}
			else {
				FOR(j, 1, w) {
					cin >> wall;
					if (wall == 1) {
						dp[i][j * 2 - 1] = 1;
					}
				}
				flag = true;
			}
		}
		pos[1][1].deep = 1;
		que.push(pos[1][1]);
		while (!que.empty()) {
			now = que.front();
			que.pop();
			if (now.xx == 2 * w - 1 && now.yy == 2 * h - 1) {
				cout << now.deep << endl;
				check = true;
				break;
			}
			if (now.xx + 2 <= 2 * w) {
				if (dp[now.yy][now.xx+1] == 0 && dp[now.yy][now.xx+2] == 0&&pos[now.yy][now.xx+2].chcked==false) {
					pos[now.yy][now.xx + 2].deep = pos[now.yy][now.xx].deep + 1;
					pos[now.yy][now.xx + 2].chcked = true;
					que.push(pos[now.yy][now.xx + 2]);
				}
			}
			if (now.xx - 2 >= 0) {
				if (dp[now.yy][now.xx - 1] == 0 && dp[now.yy][now.xx - 2] == 0&& pos[now.yy][now.xx - 2].chcked == false) {
					pos[now.yy][now.xx - 2].deep = pos[now.yy][now.xx].deep + 1;
					pos[now.yy][now.xx - 2].chcked = true;
					que.push(pos[now.yy][now.xx - 2]);
				}
			}
			if (now.yy + 2 <= 2 * h) {
				if (dp[now.yy+1][now.xx] == 0 && dp[now.yy+2][now.xx] == 0&& pos[now.yy+2][now.xx].chcked == false) {
					pos[now.yy+2][now.xx].deep = pos[now.yy][now.xx].deep + 1;
					pos[now.yy + 2][now.xx].chcked = true;
					que.push(pos[now.yy+2][now.xx]);
				}
			}
			if (now.yy - 2 >=0) {
				if (dp[now.yy - 1][now.xx] == 0 && dp[now.yy - 2][now.xx] == 0&& pos[now.yy - 2][now.xx].chcked == false) {
					pos[now.yy - 2][now.xx].deep = pos[now.yy][now.xx].deep + 1;
					pos[now.yy - 2][now.xx].chcked = true;
					que.push(pos[now.yy - 2][now.xx]);
				}
			}
		}
		if (!check) {
			cout << 0 << endl;
		}
	}
	
}

C++: #include <iostream>
#include <queue>
#include <string.h>

using namespace std;

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

int main(){
    int w, h;
    string s[59];
    int step[30][30];
    while(cin >> w >> h, w){
        getline(cin, s[0]);
        for(int i=0;i<2*h-1;i++) getline(cin, s[i]);
        for(int i=0;i<2*h-1;i++) s[i] += " ";
        memset(step, -1, sizeof(step));
        queue< pair<int, int> > qu; qu.push(make_pair(0,0));
        step[0][0] = 1;
        while(!qu.empty()){
            pair<int, int> p = qu.front(); qu.pop();
            int x = p.first, y = p.second;
            for(int i=0;i<4;i++){
                int nx = x+dx[i], ny = y+dy[i];
                if(nx<0||h<=nx||ny<0||w<=ny) continue;
                if(s[2*x+dx[i]][2*y+dy[i]]=='1') continue;
                if(step[nx][ny]!=-1) continue;
                step[nx][ny] = step[x][y] + 1;
                qu.push(make_pair(nx, ny));
            }
        }
        cout << (step[h-1][w-1] == -1 ? 0 : step[h-1][w-1]) << endl;
    }
}