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<algorithm>
#include<map>
#include<queue>

using namespace std;

typedef pair<int, int> P;

const int dx[4]={0,0,1,-1};
const int dy[4]={1,-1,0,0};


int solve(int a[100][100],int w,int h){
	int d[100][100]={0};
	d[1][1]=1;

	P sp(1,1);
	queue<P> q;
	q.push(sp);

	while(!q.empty()){
		P 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(a[my][mx]==0 && d[ny][nx]==0){
				P np(nx,ny);
				q.push(np);
				d[ny][nx]=cnt+1;
			}
		}
	}
	return d[h*2-1][w*2-1];
}


int main(){
	int x,y;

	while(cin>>x>>y,x||y){
		
		int MazeWall[100][100]={0};
		
		for(int xr=0;xr<=x*2;xr++){
			MazeWall[0][xr]=MazeWall[y*2][xr]=1;
		}

		for(int yr=0;yr<=y*2;yr++){
			MazeWall[yr][0]=MazeWall[yr][x*2]=1;
		}
		
		
		for(int yr=0;yr<(y*2-1);yr++){
			if(yr%2==0){
				for(int xr=0;xr<x-1;xr++){
					//(x,y)=>(2xr+2,yr+1);
					cin>>MazeWall[yr+1][xr*2+2];
				}
			}
			else{
				for(int xr=0;xr<x;xr++){
					//(x,y)=>(2xr+1,yr+1);
					cin>>MazeWall[yr+1][xr*2+1];
				}
			}
		}
		cout<<solve(MazeWall,x,y)<<endl;
	}
}

C++: #include <vector>
#include <list>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <deque>
#include <algorithm>
#include <utility>
#include <functional>
#include <sstream>
#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <climits>
#include <cassert>
using namespace std;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<string> vs;
typedef pair<int, int> pii;
typedef long long ll;
#define ALL(a) (a).begin(), (a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define EXIST(s, e) ((s).find(e)!=(s).end())
#define FOR(i,a,b) for(int i=(a); i<(b); ++i)
#define REP(i,n) FOR(i, 0, n)

typedef vector<vvi> vvvi;
typedef vector<vvvi> vvvvi;

int main() {
	int W, H;
	while (cin >> W >> H, W || H) {
		vvi visited = vvi(H, vi(W, false));
		vvvvi wall = vvvvi(H, vvvi(W, vvi(H, vi(W, false))));
		REP(i, H) {
			REP(j, W-1) {
				bool b; cin >> b;
				if (b) {
					wall[i][j][i][j+1] = true;
					wall[i][j+1][i][j] = true;
				}
			}
			if (i == H-1) break;
			REP(j, W) {
				bool b; cin >> b;
				if (b) {
					wall[i][j][i+1][j] = true;
					wall[i+1][j][i][j] = true;
				}
			}
		}



		int ans = 0;
		// < y, x >, steps
		queue<pair<pii, int> > q;
		q.push(make_pair(pii(0, 0), 1));
		while(!q.empty()) {
			pair<pii, int> t = q.front(); q.pop();
			int y = t.first.first, x = t.first.second;
			int cost = t.second;

			if(visited[y][x]) continue;
			visited[y][x] = true;

			// fprintf(stderr, "visiting (%d, %d)\n", y, x);
			// Goal
			if (y == H-1 && x == W-1) {
				// cerr << "Goal" << endl;
				ans = cost;
				break;
			}

			int dy[] = {-1, 0, 1, 0}, dx[] = {0, 1, 0, -1};
			REP(d, 4) {
				int ny = y + dy[d], nx = x + dx[d];
				if ( !((0 <= ny && ny < H) && (0 <= nx && nx < W)) ) {
					continue;
				}
				if ( wall[y][x][ny][nx] ) continue;

				q.push(make_pair(pii(ny, nx), cost + 1));
			}
		}

		cout << ans << endl;
	}
}

C++: #include<iostream>
#include<queue>
using namespace std ;

int map[200][200] = {} ;
int dx[] = { -1,0,1,0 } ;
int dy[] = { 0,-1,0,1 } ;

queue<int> count ;
queue<int> x ;
queue<int> y ;

int main(){
	
	int w , h ;
	int nx , ny , nc ;
	
	while(1){
		cin >> w >> h ;
		if( w==0 && h==0 ) break ;
		
		for( int i=0 ; i<=(h-1)*2 ; i++ ){
			for( int j=(i+1)%2 ; j<=(w-1)*2 ; j += 2  ){
				cin >> map[i][j] ;
			}
		}
		
		count.push(1) ;
		x.push(0) ;
		y.push(0) ;
		
		while(1){
			if( count.empty() ){
				cout << 0 << endl ;
				break ;
			}
			else if( x.front() == (w-1)*2 && y.front() == (h-1)*2 ){
				cout << count.front() << endl ;
				break ;
			}
			
			nc = count.front() ;
			nx = x.front() ;
			ny = y.front() ;
			count.pop() ;
			x.pop() ;
			y.pop() ;
			
			for( int i=0 ; i<4 ; i++ ){
				if( nx+dx[i]*2 >= 0 && nx+dx[i]*2 <= (w-1)*2 &&
					ny+dy[i]*2 >= 0 && ny+dy[i]*2 <= (h-1)*2 &&
					map[ ny+dy[i]*2 ][ nx+dx[i]*2 ] == 0 &&
					map[ ny+dy[i] ][ nx+dx[i] ] == 0 ){
					map[ ny+dy[i]*2 ][ nx+dx[i]*2 ] = nc+1 ;
						x.push( nx+dx[i]*2 ) ;
						y.push( ny+dy[i]*2 ) ;
						count.push( nc+1 ) ;
				}
			}
		}
		
		while(1){
			if( count.empty() ) break ;
			else{
				count.pop() ;
				x.pop() ;
				y.pop() ;
			}
		}
		
		for( int i=0 ; i<=(h-1)*2 ; i++ ){
			for( int j=0 ; j<=(w-1)*2 ; j++ ){
				map[i][j] = 0 ;
			}
		}
	}
	
return 0 ;
}