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 <algorithm>
#include <map>
using namespace std;

#define REP(i,n) for (int i = 0; i < (int)(n); ++i)
#define FOR(i,p,k) for (int i = p; i <= (int)(k); ++i)
#define FOREACH(it,x) for (__typeof((x).begin()) it = (x).begin(); it != (x).end(); ++it)
#define ALL(x) x.begin(), x.end()

template<class K, class V> ostream& operator<<(ostream& os, const pair<K,V>& p) { os << '<' << p.first << ',' << p.second << '>'; return os; }
template<class T> ostream& operator<<(ostream& os, const vector<T>& v) { REP(i,v.size()) os<<'['<<v[i]<<']'; return os; }
template<class K, class V> ostream& operator<<(ostream& os, const map<K,V>& m) { FOREACH(it,m) os<<'{'<<it->first<<':'<<it->second<<'}'; return os; }
#define DEBUG(x) cerr<<#x":"<<(x)<<" "

template<class T> void DUMP(const T& v) { FOREACH(it,v) cerr<<*it<<' '; cerr<<endl; }

typedef pair<int, int> pt;
#define x first
#define y second

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

int main() {
  int w, h, W, H;
  while (cin >> w >> h, w && h) {
    W = 2*w-1;
    H = 2*h-1;
    vector<string> room(H);
    vector<vector<int> > visited(H, vector<int>(W));
    getline(cin, room[0]);
    REP(i, H) {
      getline(cin, room[i]);
      if (i % 2 == 0) room[i] += ' ';
    }
    // DEBUG(room);
    vector<pt> cur(1, pt(0,0));
    vector<pt> nex;
    int res = 0;
    for (int level = 0; cur.size(); level++) {
      //DEBUG(cur)<<endl;
      nex.clear();
      REP(i, cur.size()) {
        int x = cur[i].x;
        int y = cur[i].y;
        if (visited[y][x]) continue;
        visited[y][x] = 1;
        if (x == W-1 && y == H-1) {
          res = level+1;
          break;
        }
        REP(d, 4) {
          int nx = x + dx[d];
          int ny = y + dy[d];
          if (nx < 0 || nx >= W || ny < 0 || ny >= H || room[ny][nx] == '1') continue;
          nex.push_back(pt(nx+dx[d], ny+dy[d]));
        }
      }
      cur.swap(nex);
    }
    cout << res << endl;
  }
  return 0;
}

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

int w,h;
int map[100][100];

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

//ÄAÖ
void check(int x,int y,int cnt){
	map[y][x] = cnt;

	//ãº¶ESûü²×é
	for(int i=0 ; i<4 ; i++){
		int mx = x + dx[i]*2;
		int my = y + dy[i]*2;

		//ãº¶E2}Xæª0ÈãE³ÈàÈç²×é
		if(mx>=0 && mx<=w*2-1 && my>=0 && my<h*2-1){
			int nx = x + dx[i];
			int ny = y + dy[i];
			//ãº¶EP}XæªÇÅÈ¢ ©Â ãº¶EQ}XæªÜ¾TõµÄ¢È¢Æ«ÄA
			if(map[ny][nx]==0 && map[my][mx]==0){
				check(mx,my,cnt+1);
			}
			//ãº¶EP}XæªÇÅÈ¢ 
			//©Â ãº¶EQ}Xæªæè­È¢èÅ½ÇèÂ¯éÆ«ÄA
			if(map[ny][nx]==0 && map[my][mx]>cnt){
				map[my][mx] = cnt;
				check(mx,my,cnt+1);
			}
		}
	}
}

int main(){

	while(1){
		//ÏÌú»
		for(int y=0 ; y<50 ; y++){
			for(int x=0 ; x<50 ; x++){
				map[y][x] = 0;
			}
		}

		//E³ÌüÍ
		cin >> w >> h;
		if(w==0 && h==0) break;//0 0üÍÅI¹

		for(int y=0 ; y < ((h*2)-1) ; y++){
			//³ªïsÚÌüÍÌÆ«(yÍ0©çnÜéÌÅy%2==0ÆÈé)
			if(y%2==0){
				for(int x=0 ; x<(w-1) ; x++){
					cin >> map[y][x*2+1];		
				}
			}
			//³ôsÚÌüÍÌÆ«
			else{
				for(int x=0 ; x<w ; x++){
					cin >> map[y][x*2];
				}
 			}
		}
		//X^[gn_(x,y)=(0,0)ÌÀWðÄAÖÉn·
		check(0,0,1);
		//¦ÌoÍ
		cout << map[2*h-2][w*2-2] << endl;
	}
}