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;
typedef long long int ll;

int dw[4] = {1,0,-1,0};
int dh[4] = {0,1,0,-1};

int main()
{
    int W,H;
    while(cin >> W >> H)
    {
        if(W == 0 && H == 0) break;
        vector<vector<vector<int>>>v(H,vector<vector<int>>(W,vector<int>(4,1)));
        for(int i = 0; i < H; i++)v[i][0][2] = 0;
        for(int i = 0; i < H; i++)v[i][W-1][0] = 0;
        for(int i = 0; i < W; i++)v[0][i][3] = 0;
        for(int i = 0; i < W; i++)v[H-1][i][1] = 0;
        for(int i = 0; i < W-1; i++)
        {
            int p;
            cin >> p;
            if(p) v[0][i][0] = 0,v[0][i+1][2] = 0;
        }
        for(int i = 1; i < H; i++)
        {
            for(int j = 0; j < W; j++)
            {
                int p;
                cin >> p;
                if(p) v[i-1][j][1] = 0,v[i][j][3] = 0;
            }
            for(int j = 0; j < W-1; j++)
            {
                int p;
                cin >> p;
                if(p) v[i][j][0] = 0,v[i][j+1][2] = 0;
            }
        }
        vector<vector<int>>G(H,vector<int>(W,-1));
        G[0][0] = 1;
        queue<pair<int,int>>que;
        que.push(make_pair(0,0));
        while(!que.empty())
        {
            int h = que.front().first;
            int w = que.front().second;
            que.pop();
            for(int i = 0; i < 4; i++)
            {
                if(v[h][w][i] == 0) continue;
                int nh = h + dh[i];
                int nw = w + dw[i];
                if(nh < 0 || nh >= H || nw < 0 || nw >= W) continue;
                if(G[nh][nw] != -1) continue;
                G[nh][nw] = G[h][w] + 1;
                que.push(make_pair(nh,nw));
            }
        }
        if(G[H-1][W-1] == -1) cout << 0 << endl;
        else cout << G[H-1][W-1] << endl;
    }
}

C++: #include<iostream>
#include<queue>
using namespace std;
int w,h;
class Node{
public:
	int x;
	int y;
	int cost;
	Node(int _x,int _y,int c){
		x=_x;
		y=_y;
		cost=c;
	}
	void print(){
		cout<<"("<<x<<","<<y<<")"<<cost<<endl;
	}
};
int dx[]={ 0, 1, 0,-1};
int dy[]={-1, 0, 1, 0};


bool visited[31][31];
typedef queue <Node> Queue;
int map[80][80];
int dijkstra(){
	Queue q;
	q.push(Node(0,0,1));
	while(!q.empty()){
		Node cur=q.front();
		q.pop();
	//	cur.print();
		if(cur.x==2*(w-1)&&cur.y==2*(h-1))return cur.cost;
		if(visited[cur.y][cur.x]==true)continue;
		visited[cur.y][cur.x]=true;
		for(int i=0;i<4;i++){
			if(cur.x+dx[i]<0||cur.x+dy[i]>2*(w-1)+1
					||cur.y+dy[i]<0||cur.y+dy[i]>2*(h-1)||map[cur.y+dy[i]][cur.x+dx[i]]==1||map[cur.y+2*dy[i]][cur.x+2*dx[i]]==1)continue;
			if(visited[cur.y+2*dy[i]][cur.x+2*dx[i]])continue;
			q.push(Node(cur.x+2*dx[i],cur.y+2*dy[i],cur.cost+1));
		}
	}

	return 0;
}
void init(){
	for(int i=0;i<31;i++){
		for(int j=0;j<31;j++){
			visited[i][j]=false;
		}
	}

}
void print(){
	for(int i=0;i<2*h-1;i++){
		for(int j=0;j<2*w-1;j++){
			cout<<map[i][j];
		}
		cout<<endl;
	}

}
int main(){
	while(true){
		cin>>w>>h;
		if(!(w||h))break;
		init();

		for(int i=0;i<2*h-1;i++){
			if(!(i%2)){
				for(int j=1;j<2*w-1;j+=2){
					cin>>map[i][j];
				}
			}
			else{
				for(int j=0;j<2*w-1;j+=2){
					cin>>map[i][j];
				}
			}
		}
//		print();
		cout<<dijkstra()<<endl;
	}



	return 0;
}

C++: #include<iostream>
#include<vector>
#include<queue>
using namespace std;
int main()
{
  queue<int> answer;
  int w,h;
  while(cin >> w >> h && !(w == 0 && h == 0)){
    vector< vector<int> > tatewall(h,vector<int>(w + 1,1)),yokowall(h + 1,vector<int>(w,1));
    for(int j = 1;j <= w - 1;++j) cin >> tatewall[0][j];
    for(int i = 1;i <= h - 1;++i){
      for(int j = 0;j < w;++j) cin >> yokowall[i][j];
      for(int j = 1;j <= w - 1;++j) cin >> tatewall[i][j];
    }
    vector< vector<int> > P(w*h);
    for(int i = 0;i < w*h;++i){
      if(yokowall[(int)(i/w)][i%w] == 0) P[i].push_back(i - w);
      if(tatewall[(int)(i/w)][i%w] == 0) P[i].push_back(i - 1);
      if(tatewall[(int)(i/w)][i%w + 1] == 0) P[i].push_back(i + 1);
      if(yokowall[(int)(i/w) + 1][i%w] == 0) P[i].push_back(i + w);
    }
    queue<int> Q;
    vector<int> check(w*h,0),D(w*h,0);
    int cur,dst;
    Q.push(0);
    D[0] = 1;
    check[0] = 1;
    while(!Q.empty()){
      cur = Q.front();
      for(int i = 0;i < P[cur].size();++i){
	dst = P[cur][i];
	if(check[dst] == 0){
	  Q.push(dst);
	  D[dst] = D[cur] + 1;
	  check[dst] = 1;
	}
      }
      Q.pop();
    }
    answer.push(D[w*h - 1]);
  }
  while(!answer.empty()){
    cout << answer.front() << endl;
    answer.pop();
  }
}