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 <cmath>
#include <cstring>

#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <unordered_map>
#include <unordered_set>

#include <complex>

#include <functional>
#include <cassert>

typedef long long ll;
using namespace std;

#define debug(x) cerr << #x << " = " << (x) << endl;


#define mod 1000000007 //1e9+7(prime number)
#define INF 1000000000 //1e9
#define LLINF 2000000000000000000LL //2e18
#define SIZE 1010

int dx[4] = {1,0,-1,0};
int dy[4] = {0,-1,0,1};
//RULD

bool solve(){
  int w,h;
  bool f[SIZE][SIZE][4] = {};
  
  scanf("%d%d",&w,&h);

  if(w + h == 0) return false;
  
  for(int i=0;i<h;i++){
    int in;
    
    for(int j=0;j<w-1;j++){
      scanf("%d",&in);

      f[i][j][0] = 1-in;
      f[i][j+1][2] = 1-in;
    }
    
    if(i+1 == h) break;

    for(int j=0;j<w;j++){
      scanf("%d",&in);

      f[i][j][3] = 1-in;
      f[i+1][j][1] = 1-in;
    }
  }

  queue<pair<int,int> > que;
  bool visited[SIZE][SIZE] = {};
  que.push({0,0});

  for(int i=1;que.size();i++){
    queue<pair<int,int> > q2;
    
    while(que.size()){
      pair<int,int> p = que.front();
      que.pop();

      int y = p.first;
      int x = p.second;
      
      if(visited[y][x]) continue;
      visited[y][x] = 1;

      if(y == h-1 && x == w-1){
        printf("%d\n",i);
        return true;
      }
      
      for(int j=0;j<4;j++){
        if(f[y][x][j]){
          q2.push({y+dy[j],x+dx[j]});
        }
      }
    }

    que = q2;
  }

  puts("0");
  
  return true;
}

int main(){

  while(solve());
  
  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;
}