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<queue>
#include<utility>
#include<cstring>
#define MP make_pair
using namespace std;
typedef pair<int, int> PII;

int w, h;
bool field[70][35];
int cost[35][35];
queue<PII> Q;

int dx[] = {0, 1, 0, -1}, dy[] = {1, 0, -1, 0};
bool judge(int x, int y)
{
  if(0 <= x && x < h && 0 <= y && y < w)
    return true;
  return false;
}

int main()
{
  while(true){
    cin >> w >> h;

    if(!w && !h)
      break;

    memset(field, false, sizeof field);
    memset(cost, 0, sizeof cost);

    for(int i = 0; i < 2 * h - 1; i++)
      for(int j = 0; j < (i % 2 ? w : w - 1); j++)
	cin >> field[i][j];

    Q.push(MP(0, 0));
    cost[0][0] = 1;

    int nowcost = 0;
    while(!Q.empty()){
      int sz = Q.size();
      nowcost++;

      for(int i = 0; i < sz; i++){
	PII now = Q.front();
	Q.pop();

	for(int j = 0; j < 4; j++){
	  PII next = MP(now.first + dx[j], now.second + dy[j]);

	  if(judge(next.first, next.second) && !field[2 * now.first + dx[j]][dy[j] == -1 ? now.second - 1 : now.second] && cost[next.first][next.second] == 0){
	    cost[next.first][next.second] = nowcost + 1;
	    Q.push(next);
	  }
	}
      }
    }

    cout << cost[h - 1][w - 1] << endl;
  }

  return 0;
}

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

using namespace std;

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

int main(){
	int maze[30][30];
	int wall[150][150];
	while(1){
		int w, h; cin>>w>>h;
		if(!w && !h) break;
		for(int i=0; i<h*2-1; i++){
			for(int j=0; j<w+i%2-1; j++){
				cin >> wall[i][j];
			}
		}
		fill(maze[0], maze[30],999);
		queue <pair<int, int> > q;
		q.push(make_pair(0, 0));
		maze[0][0]=1;

		while(!q.empty()){
			int y = q.front().first;
			int x = q.front().second;
			q.pop();

			for(int i=0; i<4; i++){
				int ny = y+dy[i];
				int nx = x+dx[i];
				if(ny<0||h<=ny||nx<0||w<=nx) continue;
				if((dx[i] != 1 && !wall[y*2+dy[i]][x+dx[i]]) || (dx[i] == 1 && !wall[y*2][x])){
					if(maze[ny][nx] > maze[y][x]+1){
						maze[ny][nx] = maze[y][x]+1;
						q.push(make_pair(ny, nx));
					}
				}
			}		
		}
		if(maze[h-1][w-1]==999)cout << 0 << endl;
		else cout << maze[h-1][w-1] << endl;
	}
	return 0;
}

C++: //15
#include<iostream>
#include<queue>
#include<algorithm>
#include<utility>

using namespace std;

int main(){
  for(int w,h;cin>>w>>h,w|h;){
    bool wall[64][64];
    fill_n(&wall[0][0],64*64,true);
    for(int y=1;y<=2*h-1;y++){
      for(int x=y%2+1;x<2*w;x+=2){
	int w;
	cin>>w;
	wall[y][x]=w;
      }
    }
    queue<pair<pair<int,int>,int> > que;
    que.push(make_pair(make_pair(1,1),1));
    bool pass[64][64]={};
    while(!que.empty()&&(que.front().first.first!=h*2-1||que.front().first.second!=w*2-1)){
      pair<int,int> point=que.front().first;
      if(!pass[point.first][point.second]){
	for(int i=0;i<4;i++){
	  int dx[]={0,1,0,-1};
	  int dy[]={1,0,-1,0};
	  if(!wall[point.first+dy[i]][point.second+dx[i]]){
	    que.push(make_pair(make_pair(point.first+dy[i]*2,point.second+dx[i]*2),que.front().second+1));
	  }
	}
	pass[point.first][point.second]=true;
      }
      que.pop();
    }
    cout<<((que.empty())?0:que.front().second)<<endl;
    }
  return 0;
}