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 R 2
#define L 3
#define D 0
#define U 1
using namespace std;

bool to[35][35][4];
int dx[4]={0,0,1,-1};
int dy[4]={1,-1,0,0};

int bfs(int sx,int sy,int gx,int gy)
{
	int ans=0;
	queue<pair<pair<int,int>,int> > q;
	q.push(make_pair(make_pair(sx,sy), 0));
	vector<vector<bool> >  done(gx+5,vector<bool>(gy+5,false));
	done[sx][sy]=true;
	while(!q.empty())
	{
		auto get=q.front();
		q.pop();
		int x=get.first.first;
		int y=get.first.second;
		if(x==gx and y==gy)
		{
			ans = get.second;
			break;
		}
		for(int i=0;i<4;i++)
		{
			int nx = get.first.first + dx[i];
			int ny = get.first.second + dy[i];
			if(to[x][y][i]==true and done[nx][ny]==false)
			{
				q.push(make_pair(make_pair(nx,ny),get.second+1));
				done[nx][ny]=true;
			}
		}
	}

	return (ans==0)? 0 : ans+1;
}

int main()
{
	int w,h;
	while(cin >> w >> h)
	{
		if(w==0 and h==0)return 0;
		for(int i=0;i<35;i++)
			for(int j=0;j<35;j++)
				for(int k=0;k<4;k++)
					to[i][j][k]=false;
		for(int i=0;i<2*h-1;i++)
		{
			if(i%2==0)
			{
				for(int j=0;j<w-1;j++)
				{
					int in;
					cin >> in;
					if(in==0)
					{
						to[j][i/2][R]=true;
						to[j+1][i/2][L]=true;
					}
				}
			}
			else
			{
				for(int j=0;j<w;j++)
				{

					int in;
					cin >> in;
					if(in==0)
					{
						to[j][i/2][D]=true;
						to[j][(i+1)/2][U]=true;
					}
				}
			}
		}

		cout << bfs(0,0,w-1,h-1) << endl;

	}

}

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];
    cout << h << " " << w << " " << step << endl;
    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;
    for (uint32_t i = 0; maze.size(); i++) {
      for (uint32_t j = 0; j < maze.size(); j++) {
        maze[i][j] = 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);

    cout << maze[h - 1][w - 1] << endl;
  }

  return 0;
}