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<stdio.h>
#include<cstring>
#include<math.h>
#include<map>
#include<bitset>
#include<iomanip>
#include<queue>
using namespace std;

#define rep(i, n) for (int i = 0; i < (int)(n); ++i)

int w, h;

int dist[100][100];
const int INF = 100000000;

int main() {
  while(true) {
    cin >> w >> h;
    if(w == 0 && h == 0) break;
    vector<int> m[100];
    rep(i, 2 * h - 1) {
      if(i % 2 == 0) {
        rep(j, w - 1) {
          int x;
          cin >> x;
          m[i].push_back(x);
        }
      } else {
        rep(j, w) {
          int x;
          cin >> x;
          m[i].push_back(x);
        }
      }
    }

    rep(i, h) {
      rep(j, w) {
        dist[i][j] = INF;
      }
    }
    // cout << dist[3][8] << endl;

    dist[0][0] = 0;

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

    queue<pair<int, int>> que;
    que.push(make_pair(0, 0));

    while(que.size()) {
      pair<int, int> p = que.front();
      que.pop();
      int x = p.first;
      int y = p.second;
      // cout << x << " " << y << endl;

      for(int i = 0; i < 4; i++) {
        int nx = x + dx[i];
        int ny = y + dy[i];
        if(0 <= nx && nx < h && 0 <= ny && ny < w && dist[nx][ny] == INF) {
          if(i == 0 && m[2*x+1][y] != 1) {
            dist[nx][ny] = dist[x][y] + 1;
            que.push(make_pair(nx, ny));
          }
          if(i == 3 && m[2*x-1][y] != 1) {
            dist[nx][ny] = dist[x][y] + 1;
            que.push(make_pair(nx, ny));
          }
          if(i == 2 && m[2*x][y-1] != 1) {
            dist[nx][ny] = dist[x][y] + 1;
            que.push(make_pair(nx, ny));
          }
          if(i == 1 && m[2*x][y] != 1) {
            dist[nx][ny] = dist[x][y] + 1;
            que.push(make_pair(nx, ny));
          }
        }
      }
    }

    // cout << m[1][1] << m[2][1] << m[3][1] << m[2][0] << endl;
    // cout << dist[2][1] << endl;
    
    // cout << m[3][4] << m[4][4] << m[5][4] << m[4][3] << endl;
    if(dist[h-1][w-1] != INF)cout << dist[h-1][w-1] + 1 << endl;
    else cout << 0 << endl;

    // while(que.size()) {
    //   que.pop();
    // }


    // rep(i, 2 * h - 1) {
    //   int size = m[i].size();
    //   rep(j, size) {
    //     m[i].pop_back();
    //   }
    // }
    // cout << m[0][0] << endl;

  }



  return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<queue>
#include<cstring>
using namespace std;
int main()
{
	int w,h;
	while(scanf(" %d %d",&w,&h),w) 
	{
		int W[h][w];
		int H[h][w];

		for(int i = 0; i < 2*h-1; ++i)
		{
			for(int j = 0; j < (i%2==0?w-1:w); ++j)
			{
				if(i%2==0)
				{
					scanf(" %d",&W[i/2][j]);
				}
				else
				{
					scanf(" %d",&H[i/2][j]);
				}
			}
		}
		queue<int> xs,ys,steps;
		xs.push(0); ys.push(0); steps.push(1);
		bool used[h][w];
		memset(used,0,sizeof(used));
		int ans=0;
		int dx[4]={1,0,-1,0},dy[4]={0,1,0,-1};
		while(!xs.empty()) 
		{
			int x=xs.front(),y=ys.front(),step=steps.front();
			xs.pop(); ys.pop(); steps.pop();
			if(y==h-1&&x==w-1)
			{
				ans=step;
				break;
			}
			for(int i = 0; i < 4; ++i)
			{
				int nx=x+dx[i],ny=y+dy[i];
				if(0<=nx&&nx<w&&0<=ny&&ny<h&&!used[ny][nx])
				{
					if( (i==0&&!W[y][x])|| (i==1&&!H[y][x]) || (i==2&&!W[y][nx]) || (i==3&&!H[ny][x]))
					{
						used[ny][nx]=true;
						xs.push(nx); ys.push(ny); steps.push(step+1);
					}
				}
			}
		}
		cout<<ans<<endl;
	}
  return 0;
}