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 <vector>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>

typedef long long LL;

//container util
//------------------------------------------
#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define SZ(a) int((a).size())
#define EACH(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i)
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort((c).begin(),(c).end())

//repetition
//------------------------------------------
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)

//constant
//--------------------------------------------
const double EPS = 1e-10;
const double PI  = acos(-1.0);

//clear memory
#define CLR(a) memset((a), 0 ,sizeof(a))

using namespace std;
int main(void)
{
  for(;;){
    vector<pair<int,int> > alist[32][32];
    queue<pair<int,pair<int,int> > > bfs;
    int steps[32][32];
    REP(i,32) REP(j,32)
      steps[j][i]=100000000;
    int w,h;
    cin >> w >> h;
    if(!w&&!h) return 0;
    REP(j,h){
      if(j)
	REP(i,w){
	  int tmp;
	  cin >> tmp;
	  if(tmp==0){
	    alist[j][i].PB(MP(j-1,i));
	    alist[j-1][i].PB(MP(j,i));
	  }
	}
      REP(i,w-1){
	int tmp;
	cin >> tmp;
	if(tmp==0){
	  alist[j][i].PB(MP(j,i+1));
	  alist[j][i+1].PB(MP(j,i));
	}
      }
    }
    for(bfs.push(MP(1,MP(0,0)));!(bfs.empty());bfs.pop()){
      int canstep=bfs.front().first;
      pair<int,int> xy=bfs.front().second;
      int x=xy.second,y=xy.first;
      if(canstep<steps[y][x]){
	steps[y][x]=canstep;
	REP(i,SZ(alist[y][x])){
	  bfs.push(MP(canstep+1,alist[y][x][i]));
	}
      }
    }
    int answer=steps[h-1][w-1];
    if(answer>10000) answer=0;
    cout << answer << endl;
  }
}

C++: #include <iostream>
#include <cstring>
#include <queue>
#include <set>
using namespace std;
int wmap[30][30];
int hmap[30][30];
int main()
{
  for(;;){
    int w,h;
    cin >> w >> h;
    if(w==0 || h==0) break;
    memset(wmap,0,sizeof(wmap));
    memset(hmap,0,sizeof(hmap));
    for(int i=0; i<h; i++){
      for(int j=0; j<w-1; j++){
        cin >> wmap[i][j];
      }
      if(i == h-1) break;
      for(int j=0; j<w; j++){
        cin >> hmap[i][j];
      }
    }
    queue< pair<int,pair<int,int> > > q;
    q.push( make_pair<int,pair<int,int> >(0,make_pair(0,0)));
    set< pair<int,int> > s;
    s.insert( make_pair<int,int>(0,0));
    bool bfind = false;
    while(!q.empty()){
      pair<int,pair<int,int> > node = q.front(); q.pop();
      int len = node.first;
      pair<int,int> pos = node.second;
      if(pos.first == w-1 && pos.second == h-1){
        bfind = true;
        cout << len+1 << endl;
        break;
      }
      if(pos.first > 0 && wmap[pos.second][pos.first-1] == 0){
        pair<int,int> pn = make_pair(pos.first-1,pos.second);
        if(s.insert(pn).second){
          q.push(make_pair<int,pair<int,int> >(len+1,pn));
        }
      }
      if(pos.first < w-1 && wmap[pos.second][pos.first] == 0){
        pair<int,int> pn = make_pair(pos.first+1,pos.second);
        if(s.insert(pn).second){
          q.push(make_pair<int,pair<int,int> >(len+1,pn));
        }
      }
      if(pos.second > 0 && hmap[pos.second-1][pos.first] == 0){
        pair<int,int> pn = make_pair(pos.first,pos.second-1);
        if(s.insert(pn).second){
          q.push(make_pair<int,pair<int,int> >(len+1,pn));
        }
      }
      if(pos.second < h-1 && hmap[pos.second][pos.first] == 0){
        pair<int,int> pn = make_pair(pos.first,pos.second+1);
        if(s.insert(pn).second){
          q.push(make_pair<int,pair<int,int> >(len+1,pn));
        }
      }
    }
    if(!bfind){
      cout << 0 << endl;
    }
  }
  return 0;
}