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 <utility>
#include <queue>
#include <string.h>
 
int map[2000][2000],visited[1000];
 
using namespace std;
int main(void)
{
    while(true) {
        queue< pair<int,int> > q;
        int w,h,res=-1;
 
        scanf("%d%d", &w, &h);
        if(!w && !h) break;
 
        memset( map, 0, sizeof(map) );
        memset( visited, 0, sizeof(map) );
 
        for(int i=0; i < h-1; i++) {
            for(int j=0; j < w-1; j++) {
                int in;
                scanf("%d", &in);
                if(!in) {
                    map[i*w+j][i*w+j+1] = 1;
                    map[i*w+j+1][i*w+j] = 1;
                }
            }
            for(int j=0; j < w; j++) {
                int in;
                scanf("%d", &in);
                if(!in) {
                    map[i*w+j][(i+1)*w+j] = 1;
                    map[(i+1)*w+j][i*w+j] = 1;
                }
            }
        }
        {
            int i=h-1;
            for(int j=0; j < w-1; j++) {
                int in;
                scanf("%d", &in);
                if(!in) {
                    map[i*w+j][i*w+j+1] = 1;
                    map[i*w+j+1][i*w+j] = 1;
                }
            }
        }
 
        q.push(make_pair(0,0));
        while(!q.empty() && res==-1) {
            int p,d;
            std::pair<int,int> t;
 
            t=q.front(); q.pop();
            p=t.first;
            d=t.second;
//            printf(":%d:",map[p][p+h]);
 if(visited[p]) continue;
            visited[p] = 1;
 
            if(p==w*h-1) {
                res = d;
            }
 
            if(map[p][p+1] && !visited[p+1])
                q.push(make_pair(p+1, d+1));
 
            if(p-1>0 && map[p][p-1] && !visited[p-1])
                q.push(make_pair(p-1, d+1));
 
            if(map[p][p+w] && !visited[p+w])
                q.push(make_pair(p+w, d+1));
 
            if(p-w >= 0 && map[p][p-w] && !visited[p-w])
                q.push(make_pair(p-w, d+1));
 
        }
        printf("%d\n", res+1);
    }
    return 0;
}

C++: #include<iostream>
#include<queue>

using namespace std;

#define MAX 30
#define INF 100000000

struct point{
	int x, y;
};

int main(){

	int w, h;
	int mize[MAX+2][MAX+2];
	int tw[MAX+2][MAX+2];
	int yw[MAX+2][MAX+2];
	point st, go, no, s;
	queue<point> qu;

		while (1){

		cin >> w >> h;
		if (w == 0 && h == 0) break;
		for (int i = 0; i <= MAX+1; i++){
			for (int j = 0; j <= MAX+1; j++){
				mize[i][j] = INF;
				tw[i][j] = 1;
				yw[i][j] = 1;
			}
		}
		for (int i = 1; i <= h; i++){
			for (int j = 1; j <= w - 1; j++){
				cin >> tw[i][j];
			}
			if (i != h){
				for (int j = 1; j <= w; j++){
					cin >> yw[i][j];
				}
			}
		}
		st.x = 1, st.y = 1;
		go.x = w, go.y = h;
		no.x = 1, no.y = 1;
		qu.push(no);
		mize[1][1] = 1;
		while (!qu.empty()){
			no = qu.front();
			qu.pop();
			if (tw[no.y][no.x] == 0 && mize[no.y][no.x] + 1 < mize[no.y][no.x + 1]){
				s.y = no.y, s.x = no.x + 1;
				mize[no.y][no.x + 1] = mize[no.y][no.x] + 1;
				qu.push(s);
			}
			if (tw[no.y][no.x - 1] == 0 && mize[no.y][no.x] + 1 < mize[no.y][no.x - 1]){
				s.y = no.y, s.x = no.x - 1;
				mize[no.y][no.x - 1] = mize[no.y][no.x] + 1;
				qu.push(s);
			}
			if (yw[no.y - 1][no.x] == 0 && mize[no.y][no.x] + 1 < mize[no.y - 1][no.x]){
				s.y = no.y - 1, s.x = no.x;
				mize[no.y - 1][no.x] = mize[no.y][no.x] + 1;
				qu.push(s);
			}
			if (yw[no.y][no.x] == 0 && mize[no.y][no.x] + 1 < mize[no.y + 1][no.x]){
				s.y = no.y + 1, s.x = no.x;
				mize[no.y + 1][no.x] = mize[no.y][no.x] + 1;
				qu.push(s);
			}
		}
		if (mize[go.y][go.x] == INF) cout << "0" << endl;
		else cout << mize[go.y][go.x] << endl;
	}

	return 0;
}