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<cstdio>
#include<string>
#include<vector>
#include<cmath>
#include<algorithm>
#include<functional>
#include<iomanip>
#include<queue>
#include<ciso646>
#include<random>
#include<map>
#include<set>
using namespace std;
typedef long long ll;
const ll MOD = 1000000007;
const ll INF = (ll)1000000007 * 1000000007;
const double PI = 3.14159265358979;
const double E = 2.718281828459045;
const double root2 = sqrt(2);
typedef pair<int, int> P;
typedef unsigned int ui;
int main() {
	int w, h;
	while (cin >> w >> h) {
		if (w == 0)break;
		int wall[32][32][32][32] = {};
		for (int i = 1; i <= w; i++) {
			wall[i][0][i][1] = 1;
			wall[i][h][i][h + 1] = 1;
		}
		for (int i = 1; i <= h; i++) {
			wall[0][i][1][i] = 1;
			wall[w][i][w + 1][i] = 1;
		}
		int c;
		for (int i = 1; i <= 2 * h - 1; i++) {
			if (i % 2) {
				for (int j = 1; j <= w-1; j++) {
					cin >> c;
					if (c) {
						wall[j][i / 2 + 1][j + 1][i / 2 + 1] = 1;
					}
				}
			}
			else {
				for (int j = 1; j <= w; j++) {
					cin >> c;
					if (c) {
						wall[j][i / 2][j][i / 2 + 1] = 1;
					}
				}
			}
		}
		vector<P> v; v.push_back({ 1,1 });
		int d[32][32];
		for (int i = 0; i <= 31; i++) {
			for (int j = 0; j <= 31; j++) {
				d[i][j] = (int)MOD;
			}
		}
		d[1][1] = 1;
		while (!v.empty()) {
			int len = v.size();
			for (int i = 0; i < len; i++) {
				int x = v[0].first; int y = v[0].second; v.erase(v.begin());
				if (d[x + 1][y] > d[x][y] + 1 && wall[x][y][x+1][y] == 0) {
					d[x + 1][y] = d[x][y] + 1;
					v.push_back({ x + 1,y });
				}
				if (d[x - 1][y] > d[x][y] + 1 && wall[x-1][y][x][y] == 0) {
					d[x - 1][y] = d[x][y] + 1;
					v.push_back({ x - 1,y });
				}
				if (d[x][y+1] > d[x][y] + 1 && wall[x][y][x][y+1] == 0) {
					d[x][y+1] = d[x][y] + 1;
					v.push_back({ x,y+1 });
				}
				if (d[x][y-1] > d[x][y] + 1 && wall[x][y-1][x][y] == 0) {
					d[x][y-1] = d[x][y] + 1;
					v.push_back({ x,y-1 });
				}
			}
		}
		if (d[w][h] == (int)MOD) {
			cout << 0 << endl;
		}
		else {
			cout << d[w][h] << endl;
		}
	}
	return 0;
}

C++: #include <cstdio>
#include <cstring>
#include <map>
#include <queue>
#include <algorithm>
using namespace std;

typedef pair<int, int> Pi;
typedef pair<Pi, int> Pii;

int w, h;
int ver[64][64], hor[64][64];

int bfs() {
  int dx[] = {1, -1, 0, 0};
  int dy[] = {0, 0, 1, -1};
  bool used[64][64];
  queue<Pii> que;
  que.push(make_pair(make_pair(0, 0), 1)); // ((x, y), step)
  memset(used, false, sizeof(used));

  while (que.size()) {
    Pii p = que.front(); que.pop();
    int x = p.first.first, y = p.first.second, step = p.second;
    if (x == w-1 && y == h-1)
      return step;
    for (int i = 0; i < 4; i++) {
      int nx = x + dx[i], ny = y + dy[i];
      if (nx < 0 || ny < 0 || nx >= w || ny >= h)
        continue;
      if (x != nx && ver[y][min(x, nx)] == 1)
        continue;
      if (y != ny && hor[min(y, ny)][x] == 1)
        continue;
      if (used[ny][nx])
        continue;
      used[ny][nx] = true;
      que.push(make_pair(make_pair(nx, ny), step+1));
    }
  }

  return 0;
}

int main(void) {
  for ( ; ; ) {
    scanf("%d %d", &w, &h);
    if (w + h == 0)
      break;
    for (int i = 0; i < h-1; i++) {
      for (int j = 0; j < w-1; j++)
        scanf("%d", ver[i]+j);
      for (int j = 0; j < w; j++)
        scanf("%d", hor[i]+j);
    }
    for (int j = 0; j < w-1; j++)
      scanf("%d", ver[h-1]+j);

    printf("%d\n", bfs());
  }
}