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[35][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<map>
#include<set>
#include<list>
#include<cmath>
#include<queue>
#include<stack>
#include<cstdio>
#include<string>
#include<vector>
#include<complex>
#include<cstdlib>
#include<cstring>
#include<numeric>
#include<sstream>
#include<iostream>
#include<algorithm>
#include<functional>

#define mp       make_pair
#define pb       push_back
#define all(x)   (x).begin(),(x).end()
#define rep(i,n) for(int i=0;i<(n);i++)

using namespace std;

typedef    long long          ll;
typedef    unsigned long long ull;
typedef    vector<bool>       vb;
typedef    vector<int>        vi;
typedef    vector<vb>         vvb;
typedef    vector<vi>         vvi;
typedef    pair<int,int>      pii;

const int INF=1<<29;
const double EPS=1e-9;

const int dx[]={1,0,-1,0},dy[]={0,-1,0,1};
int w,h;//幅と高さ
int solve(int board[80][80]){
	int d[100][100] ={0};
	d[1][1] = 1;
	pii sp(1,1);
	queue<pii> q;
	q.push(sp);
	while(!q.empty()){
		pii p = q.front();
		q.pop();
		int x = p.first;
		int y = p.second;
		int cnt =d[y][x];
		if(x==w*2-1&&y==h*2-1){
			break;
		}
		for(int i = 0;i < 4;i++){
			int mx = x+dx[i];
			int my = y+dy[i];
			int nx =mx +dx[i];
			int ny = my+dy[i];
			if( nx < 0 || ny < 0 || nx > w*2 || ny > h*2 ) continue;
			if( board[my][mx] == 0 && d[ny][nx] == 0 ){
				pii np( nx , ny );
				q.push( np );
				d[ny][nx] = cnt+1;
			}
		}
	}
	return d[h*2-1][w*2-1];
}
int main(){
	while(cin>>w>>h,w||h){
		int board[80][80]={0};
		for(int x = 0; x<=w*2;x++){
			board[0][x] =board[h*2][x] = 1;
		}
		for(int y = 0; y<=h*2;y++){
			board[y][0] =board[y][w*2] = 1;
		}
		for(int y = 0; y<(h*2-1);y++){
			if(y%2==0){
				for(int x= 0; x<w-1;x++){
					//(2x+2,y+1)
					cin>>board[y+1][2*x+2];
				}
			}else{
				for(int x = 0; x<w;x++){
					//(2x+1,y+1)
					cin>>board[y+1][2*x+1];
				}
			}
		}
		cout <<solve(board)<<endl;
	}
	return 0;
}

C++: #include<iostream>
using namespace std;
#define MAX 200

int field[MAX][MAX];
int cost[MAX][MAX];
int w, h;
int tmp = 1;
int ans;

int dx[4] = {2, 0, -2, 0};
int dy[4] = {0, 2, 0, -2};

void dfs(int x, int y){

	if(0 <= x && x <= h*2-1 && 0 <= y && y <= w*2-1 && tmp < cost[x][y]){
		cost[x][y] = tmp;
		tmp++;

		for(int i=0; i < 4; i++){
			if(dx[i] != 0){
				if(field[x + dx[i]/2][y + dy[i]] == 0){
					dfs(x+dx[i], y+dy[i]);
				}
			}
			else {
				if(field[x + dx[i]][y + dy[i]/2] == 0){
					dfs(x+dx[i], y+dy[i]);
				}
			}
		}
	}
}

int main(){

	while(1){
	tmp = 1;
	cin >> w >> h;
	if(w ==0 && h == 0) break;


	for(int i=0; i < h*2-1; i++){
		for(int j=0; j < w*2-1; j++){
			cost[i][j] = 1000000;
		}
	}

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

	dfs(0, 0);

	ans = cost[(h-1)*2][(w-1)*2];
	if(ans != 1000000){
		cout << ans << endl;
	}
	else {
		cout << '0' << endl;
	}

	}
}