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 <map>
#include <queue>
using namespace std;
typedef pair<int,int> P;

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

void debug(int a[100][100]){
	for(int y=0 ; y <= h*2 ; y++ ){
		for(int x=0 ; x <= w*2 ; x++ ){
			cout << a[y][x];
		}
		cout << endl;
	}
}

int solve(int a[100][100]){
	int d[100][100] = {0};
	d[1][1] = 1;

	P sp(1,1);
	queue<P> q;
	q.push( sp );

	while( !q.empty() ){
		P p = q.front();
		q.pop();
		int x = p.first;
		int y = p.second;
		int cnt = d[y][x];

		if( x == w*2-1 && y == h*2-1 ) break;

		for(int i=0 ; i < 4 ; i++ ){
			int mx = x + dx[i];
			int my = y + dy[i];
			int nx = mx + dx[i];
			int ny = my + dy[i];
			if( nx < 0 || ny < 0 || nx > w*2 || ny > h*2 ) continue;
			
			if( a[my][mx] == 0 && d[ny][nx] == 0 ){
				P np( nx , ny );
				q.push( np );
				d[ny][nx] = cnt+1;
			}
		}
	}
	return d[h*2-1][w*2-1];
}

int main(){
	while( cin >> w >> h , w||h ){
		int a[100][100] = {0};
		for(int x=0 ; x <= w*2 ; x++ ){
			a[0][x] = a[h*2][x] = 1;
		}
		for(int y=0 ; y <= h*2 ; y++ ){
			a[y][0] = a[y][w*2] = 1;
		}

		for(int y=0 ; y < (h*2-1) ; y++ ){
			if( y%2 == 0 ){
				for(int x=0 ; x < w-1 ; x++ ){
					//(x,y) => (2x+2,y+1);
					cin >> a[y+1][2*x+2];
				}
			}else{
				for(int x=0 ; x < w ; x++ ){
					//(x,y) => (2x+1,y+1);
					cin >> a[y+1][2*x+1];
				}
			}
		}
		cout << solve( a ) << endl;
	}
}

C++: #include<bits/stdc++.h>
using namespace std;

struct point{
    int x,y,cnt;
};

char maze[60][60]={0};
int dx[4] = {0,1,0,-1}, dy[4] = {-1,0,1,0};
int checked[60][60] = {0};

int main(){
    int w,h;
    while(scanf("%d %d",&w,&h),w!=0||h!=0){
        for(int i=0;i<2*h-1;++i){
            for(int j=0;j<2*w-1;++j){
                checked[i][j] = INT_MAX;
                maze[i][j] = 0;
            }
        }
        maze[0][0] = 'S';
        maze[2*(h-1)][2*(w-1)] = 'G';

        for(int i=0;i<2*h-1;++i){
            if((i&1) == 0){
                for(int j=0;j<w-1;++j){
                    int c;
                    scanf(" %d",&c);
                    if(c == 1)maze[i][2*j+1] = '#';
                }
            }else{
                for(int j=0;j<w;++j){
                    int c;
                    scanf("%d ",&c);
                    if(c == 1)maze[i][2*j] = '#';
                }
            }
        }

        queue<point> que;
        checked[0][0] = 0;
        que.push((point){0,0,1});
        bool flag = false;
        while(!que.empty()){
            point now = que.front(); que.pop();
            if(maze[now.y][now.x] == 'G'){
                printf("%d\n",now.cnt);
                flag = true;
                break;
            }
            for(int i=0;i<4;++i){
                if(now.x+dx[i]*2 >= 0 && now.x+dx[i]*2 < 2*w-1 && now.y+dy[i]*2 >= 0 && now.y+dy[i]*2 < 2*h-1 \
                    && maze[now.y+dy[i]][now.x+dx[i]] != '#'){
                    if(now.cnt+1 < checked[now.y+dy[i]*2][now.x+dx[i]*2]){
                        que.push((point){now.x+dx[i]*2,now.y+dy[i]*2,now.cnt+1});
                        checked[now.y+dy[i]*2][now.x+dx[i]*2] = now.cnt + 1;
                    }
                }
            }
        }
        if(!flag)printf("0\n");
    }

    return 0;
}