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 <bits/stdc++.h>
#define rep(i, a, n) for(int i = a; i < n; i++)
#define REP(i, n) rep(i, 0, n)
#define repb(i, a, b) for(int i = a; i >= b; i--)
#define all(a) a.begin(), a.end()
#define int long long
#define chmax(x, y) x = max(x, y)
#define chmin(x, y) x = min(x, y)
using namespace std;
typedef pair<int, int> P;
const int mod = 1000000007;
const int INF = 1e12;

int w, h;
int yoko[31][31], tate[31][31], d[31][31];
int dy[4] = {1, -1, 0, 0};
int dx[4] = {0, 0, 1, -1};
bool contain(int y, int x){
   return (0 <= y && y < h && 0 <= x && x < w);
}

signed main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    while(1){
        cin >> w >> h;
        if(w + h == 0) break;
        for(int i = 0; i < 2 * h - 1; i++){
            if(i % 2 == 0){
                rep(j, 0, w - 1){
                    cin >> yoko[i / 2][j];
                }
            }else{
                rep(j, 0, w){
                    cin >> tate[i / 2][j];
                }
            }
        }
        rep(i, 0, 31) rep(j, 0, 31) 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();
            int y = p.first;
            int x = p.second;
            if(y == h - 1 && x == w - 1){
                break;
            }
            rep(i, 0, 4){
                int ny = y + dy[i];
                int nx = x + dx[i];
                if(!contain(ny, nx)) continue;
                if(d[ny][nx] != INF) continue;
                if(i == 0){
                    if(tate[y][x]) continue;
                }else if(i == 1){
                    if(tate[y - 1][x]) continue;
                }else if(i == 2){
                    if(yoko[y][x]) continue;
                }else if(i == 3){
                    if(yoko[y][x - 1]) continue;
                }
                d[ny][nx] = d[y][x] + 1;
                q.push(P(ny, nx));
            }
        }
        int ans = d[h - 1][w - 1];
        if(ans == INF) cout << 0 << endl;
        else cout << ans << endl;
    }    
}

C++: #include<bits/stdc++.h>
using namespace std;
#define int long long
#define pb push_back 
#define pf push_front 
#define mp make_pair
#define fr first
#define sc second
#define Rep(i,n) for(int i=0;i<(n);i++)
#define All(v) v.begin(),v.end()
typedef pair<int, int> Pii; typedef pair<int, Pii> Pip;
const int INF = 1107110711071107;
int dx[4] = {0, 1, 0 ,-1}, dy[4] = {-1, 0, 1, 0};

main()
{
  int w, h;
  bool data[101][101][4];
  
  while( cin >> w >> h, !(w == 0 && h == 0) ) {
    int ans = 0;
    fill_n(**data, 101*101*4, false);
    
    for(int i=0; i<h*2-1; i++) {
      int a;
      if( i % 2 == 0 ) {
	for(int j=0; j<w-1; j++) {
	  cin >> a;
	  data[i/2][j][1] = data[i/2][j+1][3] = a;
	}
      }
      
      else { 
	for(int j=0; j<w; j++) {
	  cin >> a;
	  data[i/2][j][2] = data[(i+1)/2][j][0] = a;
	}
      }
      
    }			    
	

    queue<Pip> q;
    bool used[101][101] = {{0}};
    q.push( Pip(0, Pii(0, 0)) );
    
    while( !q.empty() ) {
      Pip p = q.front(); q.pop();
      int c = p.fr, y = p.sc.fr, x = p.sc.sc;
     
      if( y == h-1 && x == w-1 ) {
	ans = c+1;
	break;
      }
      
      if( used[y][x] ) continue;
      used[y][x] = true;

      Rep(i, 4) {
	int nx = x + dx[i], ny = y + dy[i];
	if( nx < 0 || nx >= w || ny < 0 || ny >= h || data[y][x][i] ) continue;
	q.push( Pip(c+1, Pii(ny, nx)) );
      }
      
    }

    cout << ans << endl;
    
  }
  
}