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 <vector>
#include <string>
#include <map>
#include <queue>
using namespace std;
#define rep(i,n) for (int i=0; i < (n); i++)

int dx[] = {0, 1, 0, -1};
int dy[] = {-1, 0, 1, 0};
const int MAX_W = 31;

struct Point {
  int x, y, dist;
  Point(int x, int y, int dist) : x(x), y(y), dist(dist) {}
};

int main() {

  string kabe = "";
  rep(i, MAX_W+2) kabe += "1";

  int w, h;
  while(cin >> w >> h, w || h) {
    vector<string> maze;
    maze.push_back(kabe); // 利便のため、迷路の周り(ここでは上側)を壁で囲う
    string s;
    getline(cin, s);
    rep(i, 2*h - 1) {
      getline(cin, s);
      if (s.size() < 2*w - 1) s += " "; // 入力の末尾の空白を補う
      s = "1" + s + "1"; // 左右に壁
      maze.push_back(s);
    }
    maze.push_back(kabe); // 下側に壁

    queue<Point> que;
    que.push(Point(1,1, 1));
    vector<vector<bool> > visited(2*h, vector<bool>(2*w, false));
    int ans = 0;
    while (!que.empty()) {
      Point p = que.front();
      que.pop();
      if (p.x == 2*w-1 && p.y == 2*h-1) {
        ans = p.dist;
        break;
      }
      if (visited[p.y][p.x]) continue;
      visited[p.y][p.x] = true;
      rep(i, 4) {
        int nx = p.x + dx[i];
        int ny = p.y + dy[i];
        if (maze[ny][nx] == '0') {
          // 一つ飛ばしで移動する
          que.push(Point(nx + dx[i], ny + dy[i], p.dist + 1));
        }
      }
    }
    cout << ans << endl;
  }
  return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <queue>
#include <utility>
using namespace std;

const int INF = (int)1e8;
typedef pair<int, int> P;

int main() {
  while(true) {
    int W, H; cin >> W >> H;
    if(W == 0 && H == 0) break;
    bool wall[H][W][4];
    const int dx[4] = { 1, 0, -1, 0 };
    const int dy[4] = { 0, -1, 0, 1 };
    for(int i = 0; i < H; i++) {
      for(int j = 0; j < W; j++) {
        wall[i][j][0] = false;
        wall[i][j][1] = false;
        wall[i][j][2] = false;
        wall[i][j][3] = false;
        if(i == 0) wall[i][j][1] = true;
        if(i == H - 1) wall[i][j][3] = true;
        if(j == 0) wall[i][j][2] = true;
        if(j == W - 1) wall[i][j][0] = true;
      }
    }
    for(int i = 0 ; i < H; i++) {
      for(int j = 0; j < W - 1; j++) {
        int s; cin >> s;
        if(s) {
          wall[i][j][0] = true;
          wall[i][j+1][2] = true;
        }
      }
      if(i != H - 1) {
        for(int j = 0; j < W; j++) {
          int s; cin >> s;
          if(s) {
            wall[i][j][3] = true;
            wall[i+1][j][1] = true;
          }
        }
      }
    }

    int d[H][W];
    for(int i = 0; i < H; i++)
      for(int j = 0; j < W; j++) d[i][j] = INF;
    queue<P> Q;
    Q.push(P(0, 0));
    d[0][0] = 1;
    while(!Q.empty()) {
      P p = Q.front(); Q.pop();
      for(int i = 0; i < 4; i++) {
        int ny = p.first + dy[i];
        int nx = p.second + dx[i];
        if(0 <= ny && ny < H && 0 <= nx && nx < W && d[ny][nx] == INF && wall[p.first][p.second][i] == 0) {
          d[ny][nx] = d[p.first][p.second] + 1;
          Q.push(P(ny, nx));
        }
      }
    }
    if(d[H-1][W-1] != INF) {
      cout << d[H-1][W-1] << endl;
    }
    else {
      cout << 0 << endl;
    }
  }
}