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<bits/stdc++.h>
using namespace std;

pair<int, int> operator+(pair<int, int> a, pair<int, int> b) {
  pair<int, int> ret;
  ret.first = a.first + b.first;
  ret.second = a.second + b.second;
  return ret;
}
pair<int, int> operator-(pair<int, int> a, pair<int, int> b) {
  pair<int, int> ret;
  ret.first = a.first - b.first;
  ret.second = a.second - b.second;
  return ret;
}

int main() {
	
	const vector<pair<int,int>> d{ {-1,0},{0,-1},{1,0},{0,1} };
	
	while(1){
		int w,h;
		cin >> w >> h;
		if(w==0 && h==0) break;
		
		vector<vector<int>> ykabe(h+2,vector<int>(w+2)),xkabe(h+2,vector<int>(w+2));
		for(int i=1; i<=h; i++){
			for(int j=1; j<w; j++) cin >> ykabe.at(i).at(j);
			if (i==h) continue;
			for(int j=1; j<w+1; j++) cin >> xkabe.at(i).at(j);
		}
		vector<vector<int>> fld(h+2,vector<int>(w+2,-1));
		for(int i=1; i<h+1; i++) for(int j=1; j<w+1; j++) fld.at(i).at(j) = 1;
		queue<pair<int,int>> que;
		vector<vector<int>> dist(h+2,vector<int>(w+2,0));
		
		que.push({1,1});
		dist.at(1).at(1) = 1;
		while(!que.empty()){
			auto p = que.front();
			que.pop();
			for(int i=0; i<4; i++){
				auto a = p + d.at(i);
				if(fld.at(a.first).at(a.second)==-1) continue;
				if(i==0 && xkabe.at(p.first-1).at(p.second)==1) continue;
				if(i==1 && ykabe.at(p.first).at(p.second-1)==1) continue;
				if(i==2 && xkabe.at(p.first).at(p.second)==1) continue;
				if(i==3 && ykabe.at(p.first).at(p.second)==1) continue;
				if(dist.at(a.first).at(a.second)==0) {
					que.push(a);
					dist.at(a.first).at(a.second) = dist.at(p.first).at(p.second)+1;
				}
			}
		}
		cout << dist.at(h).at(w) << endl;
	}
}

C++: #include <iostream>
#include <vector>
#include <string>
#include <queue>
using namespace std;
int main() {
  int w, h, x, y, c, ans;
  string l;
  vector<string> M0, M1;
  queue< vector<int> > que;
  while (cin >> w >> h, w) {
    getline(cin, l);
    for (int i = 0; i < 2*h-1; ++i) {
      getline(cin, l);
      if (i%2) M1.push_back(l);
      else M0.push_back(l);
    }
    vector<int> p(3,0);
    vector< vector<bool> > maze(h, vector<bool>(w, false));
    maze[0][0] = true;
    que.push(p);
    ans = 0;
    while (que.size() > 0) {
      x = que.front()[0];
      y = que.front()[1];
      c = que.front()[2];
      que.pop();
      if (x == w-1 && y == h-1) {
	ans = c+1;
	break;
      } else if (c > 900) break;
      ++c;
      if (x > 0 && M0[y][2*(x-1)+1] == '0' && (!maze[y][x-1])) {
	p = {x-1,y,c};
	que.push(p);
	maze[y][x-1] = true;
      }
      if (x < w - 1 && M0[y][2*x+1] == '0' && (!maze[y][x+1])) {
	p = {x+1,y,c};
	que.push(p);
	maze[y][x+1] = true;
      }
      if (y > 0 && M1[y-1][2*x] == '0' && (!maze[y-1][x])) {
	p = {x,y-1,c};
	que.push(p);
	maze[y-1][x] = true;
      }
      if (y < h - 1 && M1[y][2*x] == '0' && (!maze[y+1][x])) {
	p = {x,y+1,c};
	que.push(p);
	maze[y+1][x] = true;
      }
    }
    while (que.size() > 0) que.pop();
    while (M1.size() > 0) M1.pop_back();
    while (M0.size() > 0) M0.pop_back();
    cout << ans << endl;
  }
  return 0;
}