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;

int main()
{
    while (1)
    {
        int w, h;
        cin >> w >> h;
        if (w == 0 && h == 0)
        {
            break;
        }
        set<tuple<int, int, int, int>> wall;
        for (int i = 0; i < h; i++)
        {
            for (int j = 0; j < w - 1; j++)
            {
                int wall_num;
                cin >> wall_num;
                if (wall_num == 0)
                {
                    continue;
                }
                wall.insert(make_tuple(i, j, i, j + 1));
                wall.insert(make_tuple(i, j + 1, i, j));
            }
            if (i == h - 1)
            {
                continue;
            }
            for (int j = 0; j < w; j++)
            {
                int wall_num;
                cin >> wall_num;
                if (wall_num == 0)
                {
                    continue;
                }
                wall.insert(make_tuple(i, j, i + 1, j));
                wall.insert(make_tuple(i + 1, j, i, j));
            }
        }
        vector<vector<int>> dist(h, vector<int>(w, -1));
        queue<pair<int, int>> q;
        q.push(make_pair(0, 0));
        dist[0][0] = 0;
        int dh[4] = {0, 0, -1, 1};
        int dw[4] = {1, -1, 0, 0};
        while (!q.empty())
        {
            pair<int, int> p = q.front();
            q.pop();
            for (int i = 0; i < 4; i++)
            {
                int hh = p.first + dh[i];
                int ww = p.second + dw[i];
                if (hh < 0 || hh >= h || ww < 0 || ww >= w)
                {
                    continue;
                }
                if (dist[hh][ww] != -1)
                {
                    continue;
                }
                if (wall.find(make_tuple(p.first, p.second, hh, ww)) == wall.end())
                {
                    dist[hh][ww] = dist[p.first][p.second] + 1;
                    q.push(make_pair(hh, ww));
                }
            }
        }
        int ans = dist[h - 1][w - 1];
        if (ans != -1)
        {
            cout << ans + 1 << endl;
        }
        else
        {
            cout << "0" << endl;
        }
    }
}

C++: #include <cstdlib>
#include <iostream>
#include <queue>
#include <vector>
using namespace std;

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);

	for(int w, h; cin >> w >> h, w;) {
		vector<vector<int> > horizontal(h, vector<int>(w - 1));
		vector<vector<int> > vertical(h - 1, vector<int>(w));
		for(int i = 0; i < h; ++i) {
			for(int j = 0; j < w - 1; ++j)
				cin >> horizontal[i][j];

			if(i + 1 < h)
				for(int j = 0; j < w; ++j)
					cin >> vertical[i][j];
		}

		vector<vector<int> > label(h, vector<int>(w, 0));
		label[0][0] = 1;
		queue<pair<int, int> > que;
		que.push(make_pair(0, 0));

		while(!que.empty()) {
			const int x = que.front().first, y = que.front().second;
			que.pop();

			if(x > 0 && !label[y][x - 1] && !horizontal[y][x - 1]) {
				label[y][x - 1] = label[y][x] + 1;
				que.push(make_pair(x - 1, y));
			}
			if(y > 0 && !label[y - 1][x] && !vertical[y - 1][x]) {
				label[y - 1][x] = label[y][x] + 1;
				que.push(make_pair(x, y - 1));
			}
			if(x < w - 1 && !label[y][x + 1] && !horizontal[y][x]) {
				label[y][x + 1] = label[y][x] + 1;
				que.push(make_pair(x + 1, y));
			}
			if(y < h - 1 && !label[y + 1][x] && !vertical[y][x]) {
				label[y + 1][x] = label[y][x] + 1;
				que.push(make_pair(x, y + 1));
			}
		}

		cout << label[h - 1][w - 1] << endl;
	}

	return EXIT_SUCCESS;
}