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 <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <climits>
#include <cfloat>
#include <ctime>
#include <cassert>
#include <map>
#include <utility>
#include <set>
#include <iostream>
#include <memory>
#include <string>
#include <vector>
#include <algorithm>
#include <functional>
#include <sstream>
#include <complex>
#include <stack>
#include <queue>
#include <numeric>
#include <list>


using namespace std;

#ifdef _MSC_VER
#define __typeof__ decltype
template <class T> int __builtin_popcount(T n) { return n ? 1 + __builtin_popcount(n & (n - 1)) : 0; }
#endif

#define foreach(it, c) for (__typeof__((c).begin()) it=(c).begin(); it != (c).end(); ++it)
#define all(c) (c).begin(), (c).end()
#define rall(c) (c).rbegin(), (c).rend()
#define clear(arr, val) memset(arr, val, sizeof(arr))

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

template <class T> void max_swap(T& a, const T& b) { a = max(a, b); }
template <class T> void min_swap(T& a, const T& b) { a = min(a, b); }

typedef long long ll;
typedef pair<int, int> pint;

const double EPS = 1e-8;
const double PI = acos(-1.0);
const int dx[] = { 0, 1, 0, -1 };
const int dy[] = { 1, 0, -1, 0 };


int main()
{
	int w, h;
	while (cin >> w >> h, w)
	{
		bool wall[32][32][4];
		clear(wall, 0);
		for (int i = 0; i < 2 * h - 1; ++i)
		{
			bool f = i & 1;
			int y = i / 2;
			for (int j = 0; j < w - !f; ++j)
			{
				int t;
				cin >> t;
				if (!f)
					wall[y][j][1] = wall[y][j + 1][3] = t;
				else
					wall[y][j][0] = wall[y + 1][j][2] = t;
			}
		}

		int d[32][32];
		const int INF = 1 << 25;
		rep (y, h) rep (x, w)
			d[y][x] = INF;
		d[0][0] = 1;
		queue<pint> q;
		q.push(pint(0, 0));
		while (!q.empty())
		{
			pint t = q.front(); q.pop();
			int x = t.first, y = t.second;
			int nc = d[y][x] + 1;

			for (int i = 0; i < 4; ++i)
			{
				int nx = x + dx[i], ny = y + dy[i];
				if (0 <= nx && nx < w && 0 <= ny && ny < h
					&& !wall[y][x][i] && nc < d[ny][nx])
				{
					d[ny][nx] = nc;
					q.push(pint(nx, ny));
				}
			}
		}
		int res = d[h - 1][w - 1];
		if (res == INF)
			res = 0;
		cout << res << endl;
	}
}

C++: #include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll,ll> pll;
typedef pair<string,string> pss; 

int main() {
  while(1) {
    ll h,w;
    cin >> w >> h;
    if(w==0&&h==0) {
      break;
    }
    vector<vector<ll>> bv(h,vector<ll> (w-1));
    vector<vector<ll>> bh(h-1,vector<ll> (w));
    for(ll i=0;i<2*h-1;i++) {
      if(i%2) {
        for(ll j=0;j<w;j++) {
          cin >> bh[i/2][j];
        }
      }
      else {
        for(ll j=0;j<w-1;j++) {
          cin >> bv[i/2][j];
        }
      }
    }
    vector<vector<ll>> ans(h,vector<ll> (w,-1));
    ans[0][0]=1;
    queue<pll> q;
    q.push(pll(0,0));
    while(q.size()) {
      ll y=q.front().first;
      ll x=q.front().second;
      q.pop();
      for(ll i=0;i<2;i++) {
        ll nx=x-1+i;
        if(nx>-1&&nx<w-1&&bv[y][nx]==0) {
          if(nx==x) {
            nx++;
          }
          if(ans[y][nx]<0) {
            ans[y][nx]=ans[y][x]+1;
            q.push(pll(y,nx));
          }
        }
      }
      for(ll i=0;i<2;i++) {
        ll ny=y-1+i;
        if(ny>-1&&ny<h-1&&bh[ny][x]==0) {
          if(ny==y) {
            ny++;
          }
          if(ans[ny][x]<0) {
            ans[ny][x]=ans[y][x]+1;
            q.push(pll(ny,x));
          }
        }
      }
    }
    if(ans[h-1][w-1]<0) {
      ans[h-1][w-1]=0;
    }
    cout << ans[h-1][w-1] << endl;
  }
}