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;


int main(){
  while(1){
  int map[62][62]={0};
  for(int i=0;i<60;i++){
    for(int j=0;j<60;j++){
      if(i%2==0&&j%2==0){
        map[i][j]=1;
      }
    }
  }
  int N,M;
  cin >> N >> M;
  if(N==0&&M==0)break;
  for(int i=0;i<=2*(M-1)+2;i++){
    for(int j=0;j<=2*(N-1)+2;j++){
      if(i==0||i==2*(M-1)+2||j==0||j==2*(N-1)+2){
        map[i][j]=1;
      }
    }
  }
  for(int i=0;i<2*M-1;i++){
    for(int j=0;j<N-(1-i%2);j++){
      int a;
      cin >> a;
      map[i+1][j+j+1-i%2+1]=a;
    } 
  }
  queue<pair<int,pair<int, int> > > Q;
  pair<int,pair<int,int> >a;
  pair<int,int>c;
  a.first=1;
  c.first=1;
  c.second=1;
  a.second=c;
  Q.push(a);
  int count=0;
  bool ok=false;
  while(Q.size()){
    pair<int,pair<int,int> > b;
    pair<int ,int>d;
    b=Q.front();
    Q.pop();
    int m[2][4]={{-1,0,0,1},{0,-1,1,0}};
    for(int i=0;i<=3;i++){
      if(b.second.first==2*M-1&&b.second.second==2*N-1){
        ok=true;
        count = b.first;
      }
      if(map[b.second.first+m[0][i]][b.second.second+m[1][i]]==0){
        map[b.second.first+m[0][i]][b.second.second+m[1][i]]=1;
        d.first=b.second.first+m[0][i]*2;
        d.second=b.second.second+m[1][i]*2;
        a.first=b.first+1;
        a.second=d;
        Q.push(a);
      }
    }
    if(ok==true)break;
  }
  if(ok==true){
    cout << count << endl;
  }else{
    cout << "0" << endl;
  }
  }
}

C++: #include <bits/stdc++.h>
typedef long long ll;
typedef long double ld;
#define rep(i,n) for(ll i=0;i<(n);i++)
#define repr(i,n) for(ll i=(n-1);i>=0;i--)
#define all(x) x.begin(),x.end()
#define br cout << "\n";
using namespace std;
const long long INF = 1e10;
const long long MOD = 1e9+7;
using Graph = vector<vector<ll>>;
using pll = pair<ll, ll>;
template<class T> inline bool chmin(T &a, T b) { if(a > b){ a = b; return true;} return false;}
template<class T> inline bool chmax(T &a, T b) { if(a < b){ a = b; return true;} return false;}

// 0 false, 1 true 
// string to int : -48
// a to A : -32
// ceil(a)  1.2->2.0
// c++17	g++ -std=c++17 a.cpp

vector<ll> dr = {-2, 2, 0, 0};
vector<ll> dc = {0, 0, 2, -2};

int main() {
    std::cout << std::fixed << std::setprecision(15);
    
    while(true){
        ll w, h; cin >> w >> h;
        if(h == 0 && w == 0){
            break;
        }
        vector<vector<string>> maze(2*h-1, vector<string>(2*w-1, "."));

        rep(i, 2*h-1){
            if(i % 2 == 0){
                rep(j, w-1){
                    ll tmp; cin >> tmp;
                    if(tmp == 1) maze[i][2*j+1] = "#";
                }
            }else{
                rep(j, w){
                    ll tmp; cin >> tmp;
                    if(tmp == 1) maze[i][2*j] = "#";
                }
            }
        }

        vector<vector<ll>> dist(2*h-1, vector<ll>(2*w-1, -1));
        queue<pair<ll, ll>> que;
        dist[0][0] = 0;
        que.push({0, 0});

        while(!que.empty()){
            pair<ll, ll> now_pos = que.front();
            ll now_row = now_pos.first;
            ll now_col = now_pos.second;
            que.pop();
            rep(i, 4){
                ll next_row = now_row + dr[i];
                ll next_col = now_col + dc[i];

                //場外ならcontinue
                if(next_row < 0 || next_row >= 2*h - 1) continue;
                if(next_col < 0 || next_col >= 2*w - 1) continue;

                //すでに訪れていたらcontinue
                if(dist[next_row][next_col] != -1) continue;

                //壁があったらcontinue
                if(maze[now_row + dr[i]/2][now_col + dc[i]/2] == "#") continue;

                //dist格納,que追加
                dist[next_row][next_col] = dist[now_row][now_col] + 1;
                que.push({next_row, next_col});
            }
        }

        /*
        rep(i, 2*h-1){
            rep(j, 2*w-1){
                cout << dist[i][j] << " ";
            }
            br;
        }
        */

        cout << dist[2*h-2][2*w-2] + 1 << endl;

    }

}