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 <algorithm>
#include <vector>
#include <queue>
using namespace std;
#define rep(i,n) for(int i=0;i<(n);i++)
using ll = long long;

struct S {
    int x, y, c;
    S() {}
    S(int a, int b, int d) : x(a), y(b), c(d) {}
};

const int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};

int W, H;

int wx[30][30], wy[30][30];

int solve() {
    queue<S> que;
    que.emplace(0, 0, 0);
    int ret = 0;

    int visited[30][30];
    for (int j = 0; j < H; j++) for (int k = 0; k < W; k++) visited[j][k] = 0;

    while (!que.empty()) {
        S st = que.front(); que.pop();

        visited[st.x][st.y] = 1;
        if (st.x == H-1 && st.y == W-1) {
            ret = st.c+1;
            break;
        }
        
        for (int d = 0; d < 4; d++) {
            int nx = st.x + dx[d], ny = st.y + dy[d];
            if (nx < 0 || nx >= H || ny < 0 || ny >= W || visited[nx][ny]) {
                continue;
            }
            if (d % 2 == 0) { // x
                int ix = (d == 0) ? st.x : nx;
                int iy = st.y;
                if (wx[ix][iy] == 0) {
                    que.emplace(nx, ny, st.c+1);
                }
            } else { // y
                int ix = st.x;
                int iy = (d == 1) ? st.y : ny;
                if (wy[ix][iy] == 0) {
                    que.emplace(nx, ny, st.c+1);
                }
            }
        }
    }

    return ret;
}

int main(){
    while(cin>>W>>H){
        if (W == 0 && H == 0) break;
        for (int j = 0; j < H; j++) {
            for (int k = 0; k < W-1; k++) {
                cin >> wy[j][k];
            }
            if (j < H-1) {
                for (int k = 0; k < W; k++) {
                    cin >> wx[j][k];
                }
            }
        }

        cout << solve() << endl;
    }
}

C++: #include<iostream>
#include<iomanip>
#include<string>
#include<cstdlib>
#include<cmath>
#include<algorithm>
#include<vector>
#include<iomanip>
using namespace std;

int field[30][30];
int hor[30][30];
int ver[30][30];
int result;
int w, h;

void calc(int H, int W, int cnt) {
	if(field[H][W]==1)
		return;
	else
		field[H][W] = 1;

	if(H==h-1 && W==w-1) {
		if(cnt < result) result = cnt;
		return;
	}

	if(H<h-1 && field[H+1][W] == 0 && hor[H][W] == 0)
		calc(H+1, W, cnt+1);
	if(W<w-1 && field[H][W+1] == 0 && ver[H][W] == 0)
		calc(H, W+1, cnt+1);
	if(H>0 && field[H-1][W] == 0 && hor[H-1][W] == 0)
		calc(H-1, W, cnt+1);
	if(W>0 && field[H][W-1] == 0 && ver[H][W-1] == 0)
		calc(H, W-1, cnt+1);
}

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

		for(int i=0; i<h; i++)
			for(int j=0; j<w; j++)
				field[i][j] = 0;

		for(int i=0; i<h*2-1; i++) {
			if(i%2==0) {
				for(int j=0; j<w-1; j++) {
					cin >> ver[i/2][j];
				}
			}
			else {
				for(int j=0; j<w; j++) {
					cin >> hor[i/2][j];
				}
			}
		}
		result = 1000;
		calc(0, 0, 1);
		if(result == 1000)
			cout << 0 << endl;
		else
			cout << result << endl;
	}
	return 0;
}

C++: #include<bits//stdc++.h>
using namespace std;
#define fr first
#define sc second
typedef pair< int , int > Pt;
const int dx[] = { 0, 1, -1, 0}, dy[] = { 1, 0, 0, -1};
int w, h, cost[30][30];
bool mas[30][30][30][30];
int bfs(){
  fill_n(cost[0],900,0);
  queue<Pt> que;cost[0][0] = 1;
  que.push(Pt(0,0));
  while(!que.empty()){
    Pt p = que.front(); que.pop();
    if(p.fr == h - 1 && p.sc == w - 1) break;
    for(int i = 0 ; i < 4 ; i++ ){
      int ny = p.fr + dy[i], nx = p.sc + dx[i];
      if(ny >= 0 && ny < h && nx >= 0 && nx < w && !cost[ny][nx] && !mas[p.fr][p.sc][ny][nx]  && !mas[ny][nx][p.fr][p.sc]){
        cost[ny][nx] = cost[p.fr][p.sc] + 1;
        que.push(Pt(ny,nx));
      }
    }
  }return cost[h-1][w-1];
}
int main(){
  while(cin >> w >> h , w){
    for(int i = 0 ; i < 2 * h - 1 ; i++ ){
      if(i % 2)
        for(int j = 0 ; j < w ; j++ ) cin >> mas[i/2][j][i/2+1][j];
      else
        for(int j = 0 ; j < w - 1 ; j++ ) cin >> mas[i/2][j][i/2][j+1];
    }cout << bfs() << endl;
  }
}