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<queue>
#include<utility>
#include<algorithm>
#define N 32
#define INF 100
#define Pair pair<int,int>
#define x first
#define y second

using namespace std;

int h, w;
int data[N][N];
bool H[N][N], V[N][N];
int X[]={-1, 0, 0, 1};
int Y[]={0, -1, 1, 0};

void init(){
  for(int i=0; i<N; ++i){
    for(int j=0; j<N; ++j){
      data[i][j]=INF;
      H[i][j]=true;
      V[i][j]=true;
    }
  }
}

void input(){
  for(int i=0; i<2*h-1; ++i){
    if(i%2){
      for(int j=0; j<w; ++j) cin >> H[i/2][j];
    }else{
      for(int j=0; j<w-1; ++j) cin >> V[i/2][j];
    }
  }
}

bool check(const Pair& p, int& k){
  if(!(p.x>=0 && p.x<h)) return false;
  if(!(p.y>=0 && p.y<w)) return false;
  if(data[p.x][p.y]<INF) return false;
  if(k==0) return !H[p.x][p.y];
  if(k==1) return !V[p.x][p.y];
  if(k==2) return !V[p.x][p.y-1];
  if(k==3) return !H[p.x-1][p.y];
  return false;
}

int bfs(){
  queue<Pair> qu;
  qu.push(Pair(0,0));
  data[0][0]=1;
  while(!qu.empty() && data[h-1][w-1]==INF){
    int s=qu.size();
    for(int i=0; i<s; ++i){
      Pair p1=qu.front(); qu.pop();
      for(int j=0; j<4; ++j){
	Pair p2(p1.x+X[j], p1.y+Y[j]);
	if(check(p2,j)){
	  data[p2.x][p2.y] = data[p1.x][p1.y] + 1;
	  qu.push(p2);
	}
      }
    }
  }
  return data[h-1][w-1];
}

int main(){
  while(1){
    cin >> w >> h;
    if(!w && !h) break;
    init();
    input();
    int ans=bfs();
    cout << (ans!=INF ? ans : 0) << endl;
  }
  return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#include<numeric>
#include<string>
#include<cmath>
#include<set>
#include<queue>
#include<bitset>
#include<iomanip>
#include<cctype>
using namespace std;
const int inf = 1001001000;

void print(vector<vector<int>> a){
	for (int i=0;i<a.size();i++){
		for (int j=0;j<a[i].size();j++){
			cout << a[i][j] << " ";
		}
		cout << endl;
	}
}

void print(vector<int> a){
    int n = a.size();
    for (int j=0;j<n;j++) {
        if (j != n-1) cout << a[j] << " ";
        else cout << a[j] << endl;
    }
}

vector<int> bfs(vector<vector<int>> &graph, int start){
	queue<int> todo;
	vector<int> dist(graph.size(),-1);
	dist[start] = 1;
	todo.push(start);
	while(!todo.empty()){
		int now = todo.front();
		todo.pop();
		for (int i=0;i<graph[now].size();i++){
			int nxt = graph[now][i];
			if (dist[nxt] != -1) continue;
			dist[nxt] = dist[now] + 1;
			todo.push(nxt);
		}
	}
	return dist;
}

int main(){
    while (true){
        int w, h; cin >> w >> h;
        string gomi; getline(cin,gomi);
        if (w == 0 && h == 0) break;
        vector<string> map(2*h+1,string(2*w+1,'1'));
        for(int i = 1; i < 2*h; i++){
            string s;
            getline(cin,s);
            if (i % 2 == 1) s = s + ' ';
            for (int j = 0; j < s.size();j++){
                map[i][j+1] = s[j];
            }
        }
        vector<vector<int>> graph;
        for (int i = 0; i < map.size(); i++){
            for (int j = 0; j < map[i].size(); j++){
                vector<int> a;
                if (i % 2 == 1){
                    if (map[i][j] == ' '){
                        if (map[i][j-1] == '0') a.push_back(i*map[i].size()+j-2);
                        if (map[i][j+1] == '0') a.push_back(i*map[i].size()+j+2);
                        if (map[i-1][j] == '0') a.push_back((i-2)*map[i].size()+j);
                        if (map[i+1][j] == '0') a.push_back((i+2)*map[i].size()+j);
                    }
                }
                graph.push_back(a);
            }
        }
        vector<int> dist = bfs(graph,map[1].size()+1);
        cout << (dist[(map.size()-2)*map[0].size()+map[0].size()-2] != -1 ? dist[(map.size()-2)*map[0].size()+map[0].size()-2] : 0) << endl;
    }

    return 0;
}