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

using namespace std;

const int inf = 1e8;

int main(){
  int H, W;
  while(cin >> W >> H, H != 0){
    int sz = H* W;
    vector<vector<int>> g(sz, vector<int>(sz));
    rep(i, sz) g[i][i] = 0;

    rep(y, H) {

      rep(x, W - 1){
        int n; cin >> n;
        if (n == 0){
          g[y * W + x].push_back(y * W + (x + 1));
          g[y * W + x + 1].push_back(y * W + x); 
        }
      }
      if(y == H - 1) break;
      rep(x, W){
        int n; cin >> n;
          if (n == 0){
          g[y * W + x].push_back((y + 1) * W + x);
          g[(y + 1) * W + x].push_back(y * W + x);
          }
      }
    }
    
    deque<tuple<int, int>> q;
    vector<int> vis(sz, inf);
    vis[0] = 0;
    q.emplace_back(0, 0);
    while(q.size() > 0){
      int h, s; tie(h, s) = q.front(); q.pop_front();
      for(auto&& k : g[h]){
          if(vis[k] == inf){
              vis[k] = s + 1;
              q.emplace_back(k, s + 1);
          }
      }
    }
    int res = vis[sz - 1] + 1;
    cout << ((res >= inf) ? 0 : res) << endl;
  }
}

C++: #include <cstdio>
#include <iostream>
#include <vector>
#include <list>
#include <cmath>
#include <fstream>
#include <algorithm>
#include <string>
#include <queue>
#include <set>
#include <map>
#include <complex>
#include <iterator>
#include <cstdlib>
#include <cstring>
#include <sstream>
#include <stack>
#include <climits>

using namespace std;

typedef long long ll;
typedef pair<int,int> pii;
double EPS=1e-10;
double EQ(double a,double b){
	return abs(a-b)<EPS;
}

void solve(){
	int t,w,h,a[4][30][30];
	while(cin>>w>>h,w||h){
		memset(a,0,sizeof(a));
		for(int i=0;i<h;i++){
			for(int j=0;j<w-1;j++){
				cin>>t;
				a[1][i][j]=a[3][i][j+1]=t;
			}
			if(i==h-1) continue;
			for(int j=0;j<w;j++){
				cin>>t;
				a[2][i][j]=a[0][i+1][j]=t;
			}
		}
		int f[30][30];
		for(int i=0;i<30;i++) for(int j=0;j<30;j++) f[i][j]=100000;
		priority_queue<pair<int,pair<int,int> > > q;
		q.push(make_pair(0,make_pair(0,0)));
		f[0][0]=0;
		int dx[]={0,1,0,-1},dy[]={-1,0,1,0};
		while(!q.empty()){
			int c=-q.top().first,x=q.top().second.first,y=q.top().second.second;
			q.pop();
			if(f[y][x]<c) continue;
			for(int i=0;i<4;i++){
				int nx=x+dx[i],ny=y+dy[i];
				if(nx<0||nx>=w||ny<0||ny>=h||a[i][y][x]) continue;
				if(c+1<f[ny][nx]){
					f[ny][nx]=c+1;
					q.push(make_pair(-(c+1),make_pair(nx,ny)));
				}
			}
		}
		if(f[h-1][w-1]==100000) cout<<0<<endl;
		else cout<<f[h-1][w-1]+1<<endl;
	}
}


int main(){
	solve();

}

C++: #include <bits/stdc++.h>
using namespace std;
const long double PI = acos(-1);
typedef long long ll;
typedef pair<int64_t,int64_t> pll;
int dx[]={1,-1,0,0,1,-1,1,-1};
int dy[]={0,0,1,-1,1,-1,-1,1};
#define rep(i,a,b) for (int64_t i = (a); i < (b); i++)
#define REP(i,n) rep(i,0,n)
#define ALL(a) begin(a),end(a)
#define sz(s) (s).size()
#define pb push_back
#define mp make_pair
#define fi first
#define se second

int main()
{
    int w,h;
    while(cin>>w>>h,w)
    {
        string s[2*h-1];getline(cin,s[0]);
        REP(i,2*h-1)getline(cin,s[i]);
        REP(i,2*h-1)s[i]+=" ";
        vector<vector<int> >step(h,vector<int>(w,-1));
        queue<pair<int,int> >q;
        step[0][0]=1;
        q.push(mp(0,0));
        while(!q.empty())
        {
            int x=q.front().fi;int y=q.front().se;q.pop();
            REP(i,4)
            {
                int xx=x+dx[i];int yy=y+dy[i];
                if(xx<0||xx>=w||yy<0||yy>=h)continue;
                if(s[2*y+dy[i]][2*x+dx[i]]=='1')continue;
                if(step[yy][xx]!=-1)continue;
                step[yy][xx]=step[y][x]+1;
                q.push(mp(xx,yy));
            }
        }
        if(step[h-1][w-1]==-1)step[h-1][w-1]=0;
        cout<<step[h-1][w-1]<<endl;
        //cout << (step[h-1][w-1] == -1 ? 0 : step[h-1][w-1]) << endl;
    }
}