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<cstring>
#include<map>
#include<queue>
using namespace std;

int dp[30][30];
bool width[30][29];
bool height[29][30];
int w,h;

inline bool ismove(int x,int y){
  return 0<=x && x<w && 0<= y && y<h && dp[x][y]==0 ;
}

int main(){
  while(cin>>w>>h && h+w){
    memset(dp,0,900);
    memset(width,0,870);
    memset(height,0,870);

    for(int i=0;i<2*h-1;i++){
      if(i%2){
	for(int j=0;j<w;j++){
	  cin>>height[i/2][j];
	}
      }else{
	for(int j=0;j<w-1;j++){
	  cin>>width[i/2][j];
	}
      }
    }

    queue<pair<int,int> > q;
    pair<int,int> p(0,0); //start 
    q.push(p);
    dp[0][0]=1;
    while(!q.empty()){ 
      p=q.front();
      q.pop();
      int x=p.first;
      int y=p.second;
      //  cout<<"x = "<<x<<" y = "<<y<<endl;
      //left
      x--;
      if(ismove(x,y) && !width[y][x]){
	q.push(make_pair(x,y));
	dp[x][y]=dp[p.first][p.second]+1;
      }
      //right
      x+=2;
      if(ismove(x,y) && !width[y][p.first]){
	q.push(make_pair(x,y));
	dp[x][y]=dp[p.first][p.second]+1;
      }
      //down
      x--;
      y++;
      if(ismove(x,y) && !height[p.second][x]){
	q.push(make_pair(x,y));
	dp[x][y]=dp[p.first][p.second]+1;
      }
      //up
      y-=2;
      if(ismove(x,y) && !height[y][x]){
	q.push(make_pair(x,y));
	dp[x][y]=dp[p.first][p.second]+1;
      }

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

  }
  return 0;
}

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

using namespace std;
using P = pair<int,int>;

enum dir{
  RIGHT = 1,
  DOWN = 2,
  LEFT = 4,
  UP = 8
};

int map[30][30];
int visited[30][30];
int dist[30][30];

int main(){
  int w,h;
  while(cin >> w >> h&&w>0&&h>0){
    for(int i=0;i<h;++i){
      for(int j=0;j<w;++j){
        map[i][j] = 0;
        visited[i][j] = 0;
        dist[i][j] = 0;
      }
    }

    //???????£?????????£?????????
    for(int i=0;i<h;++i){
      map[i][0] |= LEFT;
      map[i][w-1] |= RIGHT;
    }

    for(int j=0;j<w;++j){
      map[0][j] |= UP;
      map[h-1][j] |= DOWN;
    }

    for(int i=0;i<2*h-1;++i){
      for(int j=0;j<w-1+i%2;++j){
        int wall;
        cin >> wall;
        if(wall){
          if(i%2){
            map[i/2][j] |= DOWN;
            map[i/2+1][j] |= UP;
          }else{
            map[i/2][j] |= RIGHT;
            map[i/2][j+1] |= LEFT;
          }
        }
      }
    }
    
    queue<P> q;
    q.push(P(0,0));
    visited[0][0] = 1;
    dist[0][0] = 1;

    int dx[4]={1,0,-1,0},dy[4]={0,1,0,-1};
    while(!q.empty()){
      auto p = q.front();q.pop();
      int y = p.first , x = p.second;

      for(int i=0;i<4;++i){
        int y2 = y+dy[i] , x2 = x+dx[i];
        if(!((map[y][x]&(1<<i))||visited[y2][x2])){
          q.push(P(y2,x2));
          dist[y2][x2] = dist[y][x] + 1;
          visited[y2][x2] = 1;
        }
      }
    }
    cout << dist[h-1][w-1] << endl;
  }
}