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;

#define MAX 30
#define INF 100000000

struct point{
	int x, y;
};

int main(){

	int w, h;
	int mize[MAX+2][MAX+2];
	int tw[MAX+2][MAX+2];
	int yw[MAX+2][MAX+2];
	point st, go, no, s;
	queue<point> qu;

		while (1){

		cin >> w >> h;
		if (w == 0 && h == 0) break;
		for (int i = 0; i <= MAX+1; i++){
			for (int j = 0; j <= MAX+1; j++){
				mize[i][j] = INF;
				tw[i][j] = 1;
				yw[i][j] = 1;
			}
		}
		for (int i = 1; i <= h; i++){
			for (int j = 1; j <= w - 1; j++){
				cin >> tw[i][j];
			}
			if (i != h){
				for (int j = 1; j <= w; j++){
					cin >> yw[i][j];
				}
			}
		}
		st.x = 1, st.y = 1;
		go.x = w, go.y = h;
		no.x = 1, no.y = 1;
		qu.push(no);
		mize[1][1] = 1;
		while (!qu.empty()){
			no = qu.front();
			qu.pop();
			if (tw[no.y][no.x] == 0 && mize[no.y][no.x] + 1 < mize[no.y][no.x + 1]){
				s.y = no.y, s.x = no.x + 1;
				mize[no.y][no.x + 1] = mize[no.y][no.x] + 1;
				qu.push(s);
			}
			if (tw[no.y][no.x + 1] == 0 && mize[no.y][no.x] + 1 < mize[no.y][no.x - 1]){
				s.y = no.y, s.x = no.x - 1;
				mize[no.y][no.x - 1] = mize[no.y][no.x] + 1;
				qu.push(s);
			}
			if (yw[no.y + 1][no.x] == 0 && mize[no.y][no.x] + 1 < mize[no.y - 1][no.x]){
				s.y = no.y - 1, s.x = no.x;
				mize[no.y - 1][no.x] = mize[no.y][no.x] + 1;
				qu.push(s);
			}
			if (yw[no.y][no.x] == 0 && mize[no.y][no.x] + 1 < mize[no.y + 1][no.x]){
				s.y = no.y + 1, s.x = no.x;
				mize[no.y + 1][no.x] = mize[no.y][no.x] + 1;
				qu.push(s);
			}
		}
		if (mize[go.y][go.x] == INF) cout << "0" << endl;
		else cout << mize[go.y][go.x] << endl;
	}

	return 0;
}

C++: #include<vector>
#include<cstdio>
#include<queue>
using namespace std;

#define f first
#define s second
#define Pii pair<int,int>

int w,h;
int dx[4] = {0, 0, 1, -1};
int dy[4] = {1, -1, 0, 0};

int bfs(vector< vector<int> > &wall, vector< vector<int> > &done) {
  queue<Pii> Q;
  Q.push(Pii(0, 0));
  done[0][0] = 1;

  while(!Q.empty()) {
    Pii p = Q.front();
    Q.pop();

    if(p.f == w-1 && p.s == h-1)
      return done[h-1][w-1];

    for(int i=0; i<4; ++i) {
      if(p.f+dx[i] >= 0 && p.f+dx[i] < w && p.s+dy[i] >= 0 && p.s+dy[i] < h)
	if((wall[p.s][p.f]>>i)%2 == 0 && done[p.s+dy[i]][p.f+dx[i]] == 0) {
	  Q.push( Pii(p.f+dx[i], p.s+dy[i]) );
	  done[p.s+dy[i]][p.f+dx[i]] = done[p.s][p.f]+1;
	}
    }
  }
  return 0;
}

int main() {

  int tmp;
  while(scanf("%d %d", &w, &h), w&&h) {
    vector< vector<int> >wall (h, vector<int>(w, 0));
    vector< vector<int> >done (h, vector<int>(w, 0));
    for(int i=0; i<2*h-1; ++i) {
      if(!(i%2))
	for(int j=0; j<w-1; ++j) {
	  scanf("%d",&tmp);
	  if(tmp) {
	    wall[i/2][j] |= 4;
	    wall[i/2][j+1] |= 8;
	  }
	}
      else
	for(int j=0; j<w; ++j) {
	  scanf("%d",&tmp);
	  if(tmp) {
	    wall[i/2][j] |= 1;
	    wall[i/2+1][j] |= 2;
	  }
	}
    }
    printf("%d\n", bfs(wall,done) );
  }
}

C++: #include <bits/stdc++.h>
using namespace std;
#define r(i,a,n) for(int i=a;i<n;i++)
#define M(a,b,c) make_pair(make_pair(a,b),c)
#define f first
#define s second
#define P pair<pair<int,int>,int >
int x,y,dx[]={1,-1,0,0},dy[]={0,0,1,-1};
string s[61];char d;
bool b[200][200];
int main(){
	while(cin>>x>>y,x){scanf("%c",&d);
		r(i,0,y+y-1)getline(cin,s[i]);
		queue<P>q;
		r(i,0,200)r(j,0,200)b[i][j]=0;
		q.push(M(0,0,1));b[0][0]=1;
		while(!q.empty()){
			P p=q.front();q.pop();
			if(p.f.f==y*2-2&&p.f.s==x*2-2){
				cout<<p.s<<endl;
				goto L;
			}
			r(i,0,4){
				if(p.f.f+dy[i]*2>=0&&p.f.s+dx[i]*2>=0)
					if(p.f.f+dy[i]*2<y*2-1&&p.f.s+dx[i]*2<x*2-1)
						if(s[p.f.f+dy[i]][p.f.s+dx[i]]=='0')
						if(!b[p.f.f+dy[i]*2][p.f.s+dx[i]*2]){
							b[p.f.f+dy[i]*2][p.f.s+dx[i]*2]=1;
							q.push(M(p.f.f+dy[i]*2,p.f.s+dx[i]*2,p.s+1));
						}
			}
		}
		cout<<-1<<endl;L:;
	}
}