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 <stdio.h>
#include "math.h"

#include <bitset>
#include <vector>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <cstring>
#include <string>
#include <sstream>
#include <algorithm>
#include <iomanip>
#include <iostream>

#define VARIABLE(x) cerr << #x << "=" << x << endl
#define BINARY(x) cerr << #x << "=" << static_cast<bitset<16> >(x) << endl;
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define REP(i,m,n) for (int i=m;i<(int)(n);i++)
#define if_range(x, y, w, h) if (0<=x && x<w && 0<=y && y<h)

const int INF = 10000000;
int dx[4]={-1, 0, 1, 0}, dy[4]={0, 1, 0, -1};
using namespace std;
typedef pair<int, int> P;

/** Problem1166 : Amazing Mazes **/
bool wall[40][40][4];
int vis[40][40];
int W, H;

void solve()
{
	queue<P> Q;
	Q.push(P(0,0));
	vis[0][0]=1;
	
	while (Q.size()) {
		P p = Q.front(); Q.pop();
		
		rep(i, 4) {
			int nx = p.first+dx[i], ny = p.second+dy[i];
			if_range(nx, ny, W, H) {
				if (vis[nx][ny]==INF) {
					if (dx[i]!=0) {
						if (!wall[nx][ny][1-dx[i]])
							Q.push(P(nx, ny));
					} else {
						if (!wall[nx][ny][2-dy[i]])
							Q.push(P(nx, ny));
					}
					vis[nx][ny]=vis[p.first][p.second]+1;
				}
			}
		}
	}
}

int main() {
	while (cin>>W>>H, W||H) {
		fill(wall[0][0], wall[0][0]+4*30*30, false);
		fill(vis[0], vis[0]+30*30, INF);
		
		rep(i, 2*H-1) {
			if (i%2==0) {
				rep(j, W-1) {
					int a; cin>>a;
					if (a) {
						wall[j][i/2][2]=true;
						wall[j+1][i/2][0]=true;
					}
				}
			} else {
				rep(j, W) {
					int a; cin>>a;
					if (a) {
						wall[j][i/2][3]=true;
						wall[j][i/2+1][1]=true;
					}
				}
			}
		}
		
		solve();
		
		cout << (vis[W-1][H-1]<INF ? vis[W-1][H-1]:0) << endl;
	}
}

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

const int INF = 30*30+1;
const int NOTUSE = 400*100;

struct Vec3{
  int x;
  int y;
  int count;
  Vec3(){
    x=0;
    y=0;
    count=1;
  }
};

int main(){

    int w,h;
    while(1){
      cin >> w >> h;
      if(w==0&&h==0){
        break;
      }
      char table[w][h];
      int counttable[w][h];
      bool hwall[w][h],wwall[w][h];
      int input;

      for(int i=0;i<w;i++){
        for(int j=0;j<h;j++){
          table[i][j] = '*';
          counttable[i][j] = INF;
          wwall[i][j] = true;
          hwall[i][j] = true;
        }
      }

      for(int i=0;i<h;i++){

        for(int j=0;j<w-1;j++){
          cin >> input;
          if(input==1){
            hwall[j][i] = false;
          }
        }
        if(i==h-1){
          break;
        }
        for(int j=0;j<w;j++){
          cin >> input;
          if(input==1){
            wwall[j][i] = false;
          }
        }
      }

      queue<Vec3> q;

      Vec3 vec,tmp;
      q.push(vec);
      while(!q.empty()){
        vec = q.front();
        q.pop();

        if(table[vec.x][vec.y]=='.'){
          continue;
        }

        table[vec.x][vec.y]='.';



        if(counttable[vec.x][vec.y] > vec.count){
          counttable[vec.x][vec.y] = vec.count;
        }

        vec.count += 1;
        tmp = vec;
        if(vec.x > 0 && hwall[vec.x-1][vec.y]){
          tmp.x = vec.x - 1;
          tmp.y = vec.y;
          q.push(tmp);
          tmp = vec;
        }

        if(vec.x < w-1 && hwall[vec.x][vec.y]){
          tmp.x = vec.x + 1;
          tmp.y = vec.y;
          q.push(tmp);
          tmp = vec;
        }

        if(vec.y < h-1 && wwall[vec.x][vec.y]){
          tmp.x = vec.x;
          tmp.y = vec.y + 1;
          q.push(tmp);
          tmp = vec;
        }

        if(vec.y > 0 && wwall[vec.x][vec.y-1]){
          tmp.x = vec.x;
          tmp.y = vec.y - 1;
          q.push(tmp);
          tmp = vec;
        }


      }



      cout << counttable[w-1][h-1] << endl;

    }




    return 0;
}