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
    rep(i, maze.size()) cout << maze[i] << "noge" << endl;

    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 <algorithm>
#include <iostream>
#include <vector>
#include <queue>
using namespace std;
using vi = vector<int>;

const int di[4] = {-1, 0, 1, 0};
const int dj[4] = {0, -1, 0, 1};

int main() {
    int w, h;
    while (cin >> w >> h, w) {
        int H = 2 * h - 1, W = 2 * w - 1;
        vector<vi> table(H, vi(W, -1));
        for (int i = 0; i < H; i++) {
            for (int j = (i % 2 == 0); j < W; j += 2) cin >> table[i][j];
        }
        queue<pair<int, int>> que; que.emplace(0, 0); table[0][0] = 1;
        while (!que.empty()) {
            auto p = que.front(); que.pop();
            int i = p.first, j = p.second;
            if (i == H - 1 && j == W - 1) break;
            for (int k = 0; k < 4; k++) {
                int ni = i + di[k] * 2, nj = j + dj[k] * 2;
                if (ni < 0 || H <= ni || nj < 0 || W <= nj) continue;
                if (table[(i + ni) / 2][(j + nj) / 2]) continue;
                if (table[ni][nj] > 0) continue;
                table[ni][nj] = table[i][j] + 1;
                que.emplace(ni, nj);
            }
        }
        cout << max(0, table[H - 1][W - 1]) << endl;
    }
    return 0;
}

C++: #include <bits/stdc++.h>
#define REP(i,n,N) for(int i=n;i<N;i++)
#define p(S) cout<<S<<endl
using namespace std;

int main() {
	int dx[4]={1,-1,0, 0};
	int dy[4]={0, 0,1,-1};
	int W,H,nowx,nowy;
	while(cin>>W>>H,W){
		int kabex[31][31][31],kabey[31][31][31],count=1;
		bool flag[31][31]={false};
		REP(j,0,H){
			REP(i,0,W-1){
				cin>>kabex[j][i][i+1];
				kabex[j][i+1][i]=kabex[j][i][i+1];
			}
			if(j==H-1) 	break;
			REP(i,0,W){
				cin>>kabey[j][j+1][i];
				kabey[j+1][j][i]=kabey[j][j+1][i];
			}
		}
		queue<pair<int, int>> qu;

		qu.push({0,0});
		flag[0][0]=true;
		while(!flag[H-1][W-1]){
			queue<pair<int, int>> tmpqu;
			while(!qu.empty()){
				nowy=qu.front().first;
				nowx=qu.front().second;
				qu.pop();
				for(int i=0;i<4;i++){
					int nexty=nowy+dy[i];
					int nextx=nowx+dx[i];
					if(nextx<W&&0<=nextx&&nexty<H&&0<=nexty){
						if(!flag[nexty][nextx]&&((i<2&&!kabex[nowy][nowx][nextx])||(i>=2&&!kabey[nowy][nexty][nowx]))){
							tmpqu.push({nexty,nextx});
							flag[nexty][nextx]=true;
						}
					}
				}
			}
			qu=tmpqu;
			if(qu.empty()){
				count=0;
				break;
			}
			count++;
		}
		p(count);
	}

	return 0;
}