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 <array>
#include <cstdint>
#include <iostream>
#include <queue>
#include <vector>

using namespace std;

void bfs(array<array<uint32_t, 30>, 30> &maze, vector<vector<uint32_t>> &vwalls,
         vector<vector<uint32_t>> &pwalls) {
  queue<pair<int32_t, int32_t>> q;

  q.push({0, 0});
  maze[0][0] = 1;

  while (!q.empty()) {
    pair<int32_t, int32_t> p = q.front();
    q.pop();
    int32_t h = p.first;
    int32_t w = p.second;
    uint32_t step = maze[h][w];
    if (pwalls[h][w] == 0 && maze[h][w + 1] == 0) {
      q.push({h, w + 1});
      maze[h][w + 1] = step + 1;
    }
    if (vwalls[h][w] == 0 && maze[h + 1][w] == 0) {
      q.push({h + 1, w});
      maze[h + 1][w] = step + 1;
    }
    if (h - 1 > 0 && vwalls[h - 1][w] == 0 && maze[h - 1][w] == 0) {
      q.push({h - 1, w});
      maze[h - 1][w] = step + 1;
    }
    if (w - 1 > 0 && pwalls[h][w - 1] == 0 && maze[h][w - 1] == 0) {
      q.push({h, w - 1});
      maze[h][w - 1] = step + 1;
    }
  }
}

int32_t main() {
  while (true) {
    int32_t w, h;
    cin >> w >> h;
    if (w == 0) break;

    array<array<uint32_t, 30>, 30> maze{{0}};
    vector<vector<uint32_t>> vwalls;
    vector<vector<uint32_t>> pwalls;
    for (uint32_t i = 0; i < 2 * h - 1; i++) {
      uint32_t block;
      if (i % 2 == 0) {
        vector<uint32_t> walls;
        for (uint32_t j = 0; j < w - 1; j++) {
          cin >> block;
          walls.push_back(block);
        }
        walls.push_back(1);
        pwalls.push_back(walls);
      } else {
        vector<uint32_t> walls;
        for (uint32_t j = 0; j < w; j++) {
          cin >> block;
          walls.push_back(block);
        }
        vwalls.push_back(walls);
      }
    }

    vector<uint32_t> senti;
    for (uint32_t j = 0; j < w; j++) {
      senti.push_back(1);
    }
    vwalls.push_back(senti);

    bfs(maze, vwalls, pwalls);

    if (maze[h - 1][w - 1] == UINT32_MAX) {
      cout << 0 << endl;
    } else {
      cout << maze[h - 1][w - 1] << endl;
    }
  }

  return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
#define inf 1e9
#define ll long long
#define ull unsigned long long
#define M 1000000007
#define P pair<int,int>
#define PLL pair<ll,ll>
#define FOR(i,m,n) for(int i=m;i<n;i++)
#define RFOR(i,m,n) for(int i=m;i>=n;i--)
#define rep(i,n) FOR(i,0,n)
#define rrep(i,n) RFOR(i,n,0)
#define all(a) a.begin(),a.end()
const int vx[4] = {0,1,0,-1};
const int vy[4] = {1,0,-1,0};
#define PI 3.14159265


void f(int w,int h){
  int maze[300][300]={};
  int d[300][300]={};
  rep(i,2*h-1){
    if(i%2==0){
      rep(j,w-1){
        cin>>maze[i][2*j+1];
      }
    }
    else{
      rep(j,w){
        cin>>maze[i][2*j];
      }
    }
  }


  rep(i,300){
    rep(j,300){
      d[i][j]=inf;
    }
  }
  d[0][0]=1;
  queue<P> q;
  q.push(P(0,0));

  while(q.size()){
    P p = q.front(); q.pop();
    for(int i=-2;i<=2;i+=2){
      for(int j=-2;j<=2;j+=2){
        if(i*j) continue;
        int x=p.first+i;
        int y=p.second+j;
        if(0<=x&&x<2*w&&0<=y&&y<2*h){
          if(i==2&&maze[y][x-1]) continue;
          if(j==2&&maze[y-1][x]) continue;
          if(i==-2&&maze[y][x+1]) continue;
          if(j==-2&&maze[y+1][x]) continue;
          if(d[y][x]>d[y-j][x-i]+1){
            d[y][x]=d[y-j][x-i]+1;
            q.push(P(x,y));
          }
        }
      }
    }
  }

  if(d[2*h-2][2*w-2]==inf){
    cout<<0<<endl;
  }
  else{
    cout<<d[2*h-2][2*w-2]<<endl;
  }
 

}


int main(){
  while(1){
    int w,h;
    cin>>w>>h;
    if(w==0) break;
    f(w,h);
  }

  return 0;
}

C++: #include<iostream>
#include<cstring>
#include<queue>
using namespace std;
int x[900][900], h, w, a, y[900], s;
queue<int>Q;
queue<int>R;
int main() {
	while (true) {
		memset(x, 0, sizeof(x));
		memset(y, 0, sizeof(y));
		cin >> w >> h;
		if (!w) { break; }
		for (int i = 0; i < h * 2 - 1; i++) {
			if (i % 2 == 1) {
				for (int j = 0; j < w; j++) {
					cin >> a;
					if (a == 0) {
						x[(i / 2) * 30 + j][(i / 2 + 1) * 30 + j] = 1;
					}
				}
			}
			else {
				for (int j = 0; j < w - 1; j++) {
					cin >> a;
					if (a == 0) {
						x[(i / 2) * 30 + j][(i / 2) * 30 + j + 1] = 1;
					}
				}
			}
		}
		Q.push(0);
		s = 1;
		y[0] = 1;
		while (y[(h-1) * 30 + (w-1)] == 0) {
			while (!Q.empty()) {
				a = Q.front();
				for (int j = 0; j < 900; j++) {
					if ((x[a][j] == 1 || x[j][a] == 1) && y[j] == 0) {
						y[j] = 1;
						R.push(j);
					}
				}
				Q.pop();
			}
			while (!R.empty()) {
				Q.push(R.front());
				R.pop();
			}
			s++;
			if (s >= 1000) { s = 0; break; }
		}
		while (!Q.empty()) {
			Q.pop();
		}
		cout << s << endl;
	}
}