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>
 
using namespace std;
 
struct Point {
  int x, y, dist;
};
 
int main() {
  int w, h;
  while(1) {
    cin >> w >> h;
    if(w == 0 && h == 0) break;
    int lr[h][w], td[h][w];
    for(int i = 0; i < h; i++) {
      for(int j = 0; j < w; j++) {
        lr[i][j] = td[i][j] = 0;
      }
    }
    for(int i = 0; i < h; i++) {
      for(int j = 0; j < w-1; j++) {
        cin >> lr[i][j];
      }
      if(i == h-1) break;
      for(int j = 0; j < w; j++) {
        cin >> td[i][j];
      }
    }
 
 
    bool visited[h][w];
    for(int i = 0; i < h; i++)
      for(int j = 0; j < w; j++)
        visited[i][j] = false;
 
    Point p;
    p.x = 0;
    p.y = 0;
    p.dist = 0;
 
    queue<Point> Q;
    Q.push(p);
 
    int ans = -1;
 
    while(!Q.empty()) {
      int d[4][2] = {{1,0}, {0,1}, {-1,0}, {0,-1}};
 
      p = Q.front();
      Q.pop();
      visited[p.y][p.x] = true;
      if(p.x == w-1 && p.y == h-1) {
        ans = p.dist;
        break;
      }
 
      for(int i = 0; i < 4; i++) {
        if(lr[p.y][p.x] && i == 0) continue;
        if(p.x-1 >= 0 && lr[p.y][p.x-1] && i == 2) continue;
        if(td[p.y][p.x] && i == 1) continue;
        if(p.y-1 >= 0 && td[p.y-1][p.x] && i == 3) continue;
 
        int nx = p.x + d[i][0];
        int ny = p.y + d[i][1];
        if(nx < 0 || nx >= w || ny < 0 || ny >= h) continue;
 
        if(visited[ny][nx]) continue;
 
        Point temp;
        temp.x = nx;
        temp.y = ny;
        temp.dist = p.dist + 1;
        Q.push(temp);
        visited[ny][nx] = true;
      }
    }
    if(ans != -1) cout << ans + 1 << endl;
    else cout << 0 << endl;
  }
  return 0;
}

C++: #include <bits/stdc++.h>
#define ALL(a)  (a).begin(),(a).end()
#define rep(i,n) for(int (i)=0;(i)<(n);(i)++)
using namespace std;
typedef long long ll;
typedef pair<int, int> P;
typedef pair<long long, long long> Pll;
typedef vector<int> vi;
typedef vector<vector<int>> vvi;
typedef vector<long long> vll;
typedef vector<vector<long long>> vvll;
template <typename T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template <typename T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
const long long INF = 1LL << 60;

int main(){
while(true){
  int w, h;
  cin >> w >> h;
  if(w == 0 && h == 0) break;
  vvi tate(h, vi(w-1));
  vvi yoko(h-1, vi(w));
  for(int i = 0; i < 2*h-1; i++){
    if(i % 2 == 0){
      for(int j = 0; j < w-1; j++){
        cin >> tate.at(i/2).at(j);
      }
    }
    else{
      for(int j = 0; j < w; j++){
        cin >> yoko.at(i/2).at(j);
      }
    }
  }

  vi dx = {1, 0, -1, 0};
  vi dy = {0, 1, 0, -1};

  queue<P> que;
  que.push(P(0, 0));
  vvi num(h, vi(w, -1));
  num.at(0).at(0) = 1;
  while(!que.empty()){
    int x = que.front().first;
    int y = que.front().second;
    que.pop();

    for(int i = 0; i < 4; i++){
      int xx = x + dx.at(i);
      int yy = y + dy.at(i);
      if(xx < 0 || xx >= w || yy < 0 || yy >= h) continue;

      if(dx.at(i) == 1 && tate.at(y).at(x) == 1) continue;
      if(dx.at(i) == -1 && tate.at(y).at(x-1) == 1) continue;
      if(dy.at(i) == 1 && yoko.at(y).at(x) == 1) continue;
      if(dy.at(i) == -1 && yoko.at(y-1).at(x) == 1) continue;

      if(num.at(yy).at(xx) == -1){
        num.at(yy).at(xx) = num.at(y).at(x) + 1;
        que.push(P(xx, yy));
      }
    }
  }
  if(num.at(h-1).at(w-1) == -1) cout << 0 << endl;
  else cout << num.at(h-1).at(w-1) << endl;
}
}