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<utility>
#include<tuple>
#include<queue>
using namespace std;

// distance, y, x
typedef tuple<int,int,int> T;

const int WMAX = 70, HMAX = 70;
const int INF = 4e6;
const int DX[4] = {0, 1, 0, -1}, DY[4] = {1, 0, -1, 0};
bool maze[HMAX][WMAX];
int dist[HMAX][WMAX];
int W, H;

int main() {
  while (cin >> W >> H and W) {
    H = 2 * H - 1, W = 2 * W - 1;
    for (int y = 0; y < H; y++) {
      for (int x = 0; x < W; x++) {
        maze[y][x] = (x % 2 == 0 || y % 2 == 0);
        dist[y][x] = INF;
      }
    }
    for (int y = 0; y < H; y++) {
      for (int x = (y + 1) % 2; x < W; x += 2) {
        bool wall;
        cin >> wall;
        maze[y][x] = !wall;
      }
    }
    /*for (int y = 0; y < H; y++) {
      for (int x = 0; x < W; x++) {
        cout << maze[y][x];
      }
      cout << endl;
    }*/
    dist[0][0] = 1;
    priority_queue<T> que;
    que.push(T(0, 0, 0));
    while (!que.empty()) {
      T t = que.top(); que.pop();
      int d = get<0>(t), y = get<1>(t), x = get<2>(t);
      // cout << "(" << d << "," << y << "," << x << ")" << endl;
      if (d > dist[y][x]) continue;
      for (int i = 0; i < 4; i++) {
        int nx = x + DX[i], ny = y + DY[i];
        if (nx < 0 || W <= nx || ny < 0 || H <= ny) continue;
        if (!maze[ny][nx]) continue;
        if (dist[ny][nx] > dist[y][x] + 1) {
          dist[ny][nx] = dist[y][x] + 1;
          que.push(T(dist[ny][nx], ny, nx));
        }
      }
    }
    int ans = (1 + dist[H-1][W-1]) / 2;
    cout << (ans < INF / 3 ? ans : 0) << endl;
    /*for (int y = 0; y < H; y++) {
      for (int x = 0; x < W; x++) {
        cout << dist[y][x] << '\t';
      }
      cout << endl;
    }*/
  }
}

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

using namespace std;

	int w,h,a,ans,tx,ty;
	bool map[62][62];
	int lap[62][62];
	
struct Node{
	int x,y,d;
	Node(int a,int b,int c){
		x=a;
		y=b;
		d=c;
	}
};
typedef struct Node node;


int main(){
	//??\????????????????????§??????????????????????????¨????????????????????????????????????
	cin>>w;
	cin>>h;
	
	while(w!=0 || h!=0){
		ans=0;
		for(int lop=0;lop<62;lop++){
			for(int lop2=0;lop2<62;lop2++){
				if(lop==0 || lop==61 || lop2==0 || lop2==61|| lop2==w*2 || lop==h*2){
					map[lop][lop2]=1;
				}else{
					map[lop][lop2]=0;
				}
				lap[lop][lop2]=0;
			}
		}
		//?????????????????´
		map[0][1]=0;
		map[h*2][w*2-1]=0;
		//??\?????£?????£
		
		for(int lop=0;lop<h*2-1;lop++){
			if(lop%2==0 || lop==0){
				for(int lop2=0;lop2<w-1;lop2++){
					cin>>a;
					if(a==1){
						if(map[lop][lop2*2+2]==0){
							map[lop][lop2*2+2]=1;
						}
						if(map[lop+1][lop2*2+2]==0){
							map[lop+1][lop2*2+2]=1;
						}
						if(map[lop+2][lop2*2+2]==0){
							map[lop+2][lop2*2+2]=1;
						}
					}
				}
			}else{
				for(int lop2=0;lop2<w;lop2++){
					cin>>a;
					if(a==1){
						if(map[lop+1][lop2*2]==0){
							map[lop+1][lop2*2]=1;
						}
						if(map[lop+1][lop2*2+1]==0){
							map[lop+1][lop2*2+1]=1;
						}
						if(map[lop+1][lop2*2+2]==0){
							map[lop+1][lop2*2+2]=1;
						}
					}
				}
			}
		}
		//?£???????????????????????????????????£?????????????????????????
		//?????¨?¨???§??????????????´???????£???????
		
		bool done[62][62]={0};
		queue<node> q;
		q.push(node(1,1,0));
		//??¨??¢?´¢??¨?????\?????????
		
		while(q.size()!=0){
			node qq=q.front();
			q.pop();
			//???????????? ??????????????¶ 1,1,0
			
			if(done[qq.y][qq.x]==0){
				//?£??????????????????????
				done[qq.y][qq.x]=1;
				//??????????????????????£??????????
				
				if(qq.x==w*2-1 && qq.y==h*2-1){
					ans=(qq.d+2)/2;
					break;
				}
				//??´????????????????????¢
				
				//cout<<"aaaa"<<endl;
				if(map[qq.y][qq.x-1]==0){
					q.push(node(qq.x-1,qq.y,qq.d+1));
				}
				if(map[qq.y-1][qq.x]==0){
					q.push(node(qq.x,qq.y-1,qq.d+1));
				}
				if(map[qq.y][qq.x+1]==0){
					q.push(node(qq.x+1,qq.y,qq.d+1));
				}
				if(map[qq.y+1][qq.x]==0){
					q.push(node(qq.x,qq.y+1,qq.d+1));
				}
			}
			//?????????????????´???0??????????????????
		}
		cout<<ans/2<<endl;
		
		cin>>w;
		cin>>h;
	}
	
	return 0;
}