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 at(x,y) (x)*30+y
using namespace std;

int main(){
	int w,h;
	while(cin >> w >> h,w||h){
		vector<vector<int>> v(w*31);
		for(int i=0;i<2*h-1;i++){
			for(int j=0;j<w-((i+1)%2);j++){
				int c;
				cin >> c;
				if(c) continue;
				if(i%2){//???
					v[at(j,i/2)].emplace_back(at(j,i/2+1));
					v[at(j,i/2+1)].emplace_back(at(j,i/2));
				} else{//?¨?
					v[at(j,i/2)].emplace_back(at(j+1,i/2));
					v[at(j+1,i/2)].emplace_back(at(j,i/2));
				}
			}
		}
		priority_queue<pair<int,int>> pq;
		pq.push(make_pair(1,at(0,0)));
		bool passed[30*30] = {0};
		int ans = 0;
		while(!pq.empty()){
			pair<int,int> x = pq.top();
			pq.pop();
			if(x.second == at(w-1,h-1)){
				ans = x.first;
				break;
			}
			
			if(passed[x.second]) continue;
			passed[x.second] = true;
			for(int unsigned i = 0;i<v[x.second].size();i++){
				pq.push(make_pair(x.first+1,v[x.second][i]));
			}
		}
		cout << ans << endl;
	}
	return 0;
}

C++: #include <iostream>
#include <memory>
#include <memory.h>
#include <queue>
#include <algorithm>
using namespace std;

typedef pair<int, int> P;
int dx[] = {1, 0, -1, 0};
int dy[] = {0, 1, 0, -1};
bool g[40][40][40][40];
int memo[40][40];

int main(){
  int w, h;
  int can;
  while(cin >> w >> h && (w || h)){
    
    memset(g, false, sizeof(g));
    for(int i = 1; i <= h * 2 - 1; i++){
      if(i % 2 == 1){
	for(int j = 1; j <= w - 1; j++){
	  cin >> can;
	  if(can == 0){
	    g[i/2+1][j][i/2+1][j+1] = true;
	    g[i/2+1][j+1][i/2+1][j] = true;
	  }
	}
	
      }else{
	for(int j = 1; j <= w; j++){
	  cin >> can;
	  if(can == 0){
	    g[i/2][j][i/2+1][j] = true;
	    g[i/2+1][j][i/2][j] = true;
	  }
	}
      }
    }
  
    memset(memo, -1, sizeof(memo));
    memo[1][1] = 1;
    queue<P> que;
    que.push(P(1, 1));
    while(!que.empty()){
      P p = que.front();
      que.pop();
      int y = p.first;
      int x = p.second;
      for(int i = 0; i < 4; i++){
	int y2 = y + dy[i];
	int x2 = x + dx[i];
	if(g[y][x][y2][x2] && memo[y2][x2] == -1){
	 
	  memo[y2][x2] = memo[y][x] + 1;
	  que.push(P(y2, x2));
	}
      }
    }
    int res = memo[h][w];
    if(res == -1) cout << 0 << endl;
    else cout << res << endl;
  }
  return 0;
}

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

static const int inf = 1000;

struct node{
  int x;
  int y;
};



int hor[36][36] = {{}};
int vir[36][36] = {{}};
int d[36][36] ;
int h,w,a = 0;

void bfs(int r,int s){

  queue <node> q;
  node locate; 
  node u,t;

  locate.y = r;
  locate.x = s;

  // cout << "lx = " << locate.x << ' ' << "ly = " << locate.y << endl;

  for(int i = 0;i < h;i++){
    for(int j = 0;j < w;j++){
      d[i][j] = inf;
    }
  }

  q.push(locate);

  d[0][0] = 1;

  while(!q.empty()){
    u = q.front(); q.pop();
    a++;
    if(hor[u.y][u.x] != 1 && u.y < h - 1  && (d[u.y][u.x] + 1 < d[u.y + 1][u.x])){
       d[u.y + 1][u.x] = d[u.y][u.x] + 1;
      t.x = u.x;
      t.y = u.y + 1; 
      q.push(t);
     
    }
    if(vir[u.y][u.x] != 1 && u.x < w - 1 && (d[u.y][u.x] + 1 < d[u.y][u.x + 1])){
      d[u.y][u.x + 1] = d[u.y][u.x] + 1;
      t.y = u.y;
      t.x = u.x + 1;
      q.push(t);
    }

    if((hor[u.y - 1][u.x] != 1) &&( u.y > 0 )&& (d[u.y][u.x] + 1 <  d[u.y - 1][u.x]) && (( vir[u.y][u.x] == 1) ||( hor[u.y][u.x] == 1))){
      d[u.y - 1][u.x] = d[u.y][u.x] + 1;
      t.x = u.x;
      t.y = u.y - 1; 
      q.push(t);
     
    }

    if((vir[u.y][u.x - 1] != 1) &&( u.x > 0 ) && (d[u.y][u.x] + 1 < d[u.y][u.x - 1]) && (( vir[u.y][u.x] == 1) ||( hor[u.y][u.x] == 1))){
      d[u.y][u.x - 1] = d[u.y][u.x] + 1;
      t.y = u.y;
      t.x = u.x - 1;
      q.push(t);
    }

    if(a > 9000000) {
      d[h - 1][w - 1] = 0;
      cout << "a =  " << a << endl;
      a = 0;
      break;
    }
    //   cout << "x = " << u.x << ' ' << "y = " << u.y << endl;
    if(u.x == w - 1 && u.y == h - 1){
      //      cout << "a =  " << a << endl;
      a = 0;
      break;
    }
  }




}


int main(){

   while(1){
    cin >> w >> h;

    // cout << " w = " << w << ' ' << "h = " << h << endl; 
     if(w == 0 && h == 0) break;

    for(int i = 0;i < h - 1;i++){
      for(int j = 0;j < w - 1;j++) cin >> vir[i][j];
      for(int j = 0;j < w ;j++) cin >> hor[i][j];
    }

    for(int j = 0;j < w - 1;j++) cin >> vir[h - 1][j];

   

    bfs(0,0);
    // cout << "a = " << a << endl;
    cout << d[h - 1][w - 1] << endl;

    for(int i = 0;i < 36;i++){
      for(int j = 0;j < 36;j++){
	vir[i][j] = 0;
	hor[i][j] = 0;
	d[i][j] = 0;

      }
    }
     }
}