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>
using namespace std;

int w,h;
int map[100][100];

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

//ÄAÖ
void check(int x,int y,int cnt){
	map[y][x] = cnt;

	//ãº¶ESûü²×é
	for(int i=0 ; i<4 ; i++){
		int mx = x + dx[i]*2;
		int my = y + dy[i]*2;

		//ãº¶E2}Xæª0ÈãE³ÈàÈç²×é
		if(mx>=0 && mx<=w*2-1 && my>=0 && my<h*2-1){
			int nx = x + dx[i];
			int ny = y + dy[i];
			//ãº¶EP}XæªÇÅÈ¢ ©Â ãº¶EQ}XæªÜ¾TõµÄ¢È¢Æ«ÄA
			if(map[ny][nx]==0 && map[my][mx]==0){
				check(mx,my,cnt+1);
			}
			//ãº¶EP}XæªÇÅÈ¢ 
			//©Â ãº¶EQ}Xæªæè­È¢èÅ½ÇèÂ¯éÆ«ÄA
			if(map[ny][nx]==0 && map[my][mx]>cnt){
				map[my][mx] = cnt;
				check(mx,my,cnt+1);
			}
		}
	}
}

int main(){

	while(1){
		//ÏÌú»
		for(int y=0 ; y<50 ; y++){
			for(int x=0 ; x<50 ; x++){
				map[y][x] = 0;
			}
		}

		//E³ÌüÍ
		cin >> w >> h;
		if(w==0 && h==0) break;//0 0üÍÅI¹

		for(int y=0 ; y < ((h*2)-1) ; y++){
			//³ªïsÚÌüÍÌÆ«(yÍ0©çnÜéÌÅy%2==0ÆÈé)
			if(y%2==0){
				for(int x=0 ; x<(w-1) ; x++){
					cin >> map[y][x*2+1];		
				}
			}
			//³ôsÚÌüÍÌÆ«
			else{
				for(int x=0 ; x<w ; x++){
					cin >> map[y][x*2];
				}
 			}
		}
		//X^[gn_(x,y)=(0,0)ÌÀWðÄAÖÉn·
		check(0,0,1);
		//¦ÌoÍ
		cout << map[2*h-2][w*2-2] << endl;
	}
}

C++: #include <iostream>
#include <queue>
using namespace std;

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

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

int main(){
    int w, h,i,j;
    int wall[200][100];
    int maze[100][100];
    for(;cin>>w>>h, w||h;){
        for(i=0;i<200;i++){
            for(j=0;j<100;j++){
                wall[i][j] = 0;
                maze[i/2][j] = 0;
            }
        }
        for(i = 0; i < 2*h-1; i++){
            for(j = 0; j < w - 1 + i%2; j++){
                cin >> wall[i][j];
            }
        }
        queue< P > que;
        que.push( P(0,0,1) );
        maze[0][0] = 1;
        P e;
        int ans = 0;
        while( !que.empty() ){
            e = que.front();
            que.pop();
            if( e.x == h-1 && e.y == w-1 ){
                    ans = e.d;
                    break;
            }
            maze[e.x][e.y] = 1;
            for(i=0;i<4;i++){
                int xx = e.x + dx[i], yy = e.y + dy[i];
                if( 0 <= xx && xx < h &&
                    0 <= yy && yy < w &&
                    maze[xx][yy] == 0){
                    if( wall[2*e.x + (1-i%2) - i*(1-i%2)][e.y-i/3] ) continue;
                    que.push( P(xx, yy, e.d+1) );
                    maze[xx][yy] = 1;
                }
            }
        }
        cout << ans << endl;
    }
    return 0;
}