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 <vector>
using namespace std;

int h, w, mini;
int vecX[30][30], vecY[30][30];

void solMaze(int x, int y, int sum, vector<vector<bool>> check) 
{
	if (x >= w || y >= h || x < 0 || y < 0 || check[y][x] || sum >= mini) {
		return;
	}

	check[y][x] = true;

	if (y == h - 1 && x == w - 1) {
		if (sum < mini) {
			mini = sum;
		}
		return;
	}

	if (vecX[y][x] == 0) {
		solMaze(x + 1, y, sum + 1, check);
	} 
	if (x >= 1) {
		if (vecX[y][x - 1] == 0) {
			solMaze(x - 1, y, sum + 1, check);
		}
	}
	if (vecY[y][x] == 0) {
		solMaze(x, y + 1, sum + 1, check);
	}
	if (y >= 1) {
		if (vecY[y - 1][x] == 0) {
			solMaze(x, y - 1, sum + 1, check);
		}
	}

}

int main(void)
{
	vector<vector<bool>> check(30, vector<bool>(30));
	while (1) {
		mini = 1000000000;
		for (int i = 0; i < 30; ++i) {
			for (int j = 0; j < 30; ++j) {
				vecX[i][j] = 0;
				vecY[i][j] = 0;
				check[i][j] = false;
			}
		}
		cin >> w >> h;
		if (w == 0) {
			break;
		}
		for (int i = 0; i < h; ++i) {
			for (int j = 0; j < w - 1; ++j) {
				cin >> vecX[i][j];
			}
			if (i != h - 1) {
				for (int j = 0; j < w; ++j) {
					cin >> vecY[i][j];
				}
			}
 		}

 		solMaze(0, 0, 1, check);

 		if (mini == 1000000000) {
 			mini = 0;
 		}
 		cout << mini << endl;

	}

	return 0;
}

C++: #include <cstdio>
#include <algorithm>
#include <iostream>
#include <vector>
#include <string>
#include <string.h>
#define INF 100
using namespace std;
int maze[33][33];
int d[33][33];
int w,h;
void solve(int i,int j,int c){
  if(i<0||i>=h) return;
  else if(j<0||j>=w) return;
  if(d[i][j]<=c) return;
  d[i][j]=c;
  //cout<<i<<","<<j<<":"<<c<<endl;
  if(!(maze[i][j]&1)) solve(i-1,j,c+1);
  if(!((maze[i][j]>>1)&1)) solve(i,j-1,c+1);
  if(!((maze[i][j]>>2)&1)) solve(i+1,j,c+1);
  if(!((maze[i][j]>>3)&1)) solve(i,j+1,c+1);
  return;
}
int main(void){
  int i,j;
  int res;
  string s;
  while(cin>>w>>h,w|h){
    getline(cin,s);
    for(i=0;i<h;i++){
      for(j=0;j<w;j++){
        maze[i][j]=0;
        d[i][j]=INF;
      }
    }
    
    for(i=0;i<((h*2)-1);i++){
      getline(cin,s);
      //cout<<i<<":"<<s<<endl;
      if(i%2==0){
        for(j=1;j<s.length();j+=2){
          if(s[j]=='1'){
            maze[i/2][j/2]+=8;
            maze[i/2][(j/2)+1]+=2;
          }
        }
      }
      else{
        for(j=0;j<s.length();j+=2){
          if(s[j]=='1'){
            maze[i/2][j/2]+=4;
            maze[(i/2)+1][j/2]+=1;
          }
        }
      }
    }
    solve(0,0,1);
    /*
    cout<<":"<<endl;
    for(i=0;i<h;i++){
      for(j=0;j<w;j++){
        //cout<<d[i][j]<<" ";
        printf("%3d ",d[i][j]);
      }
      cout<<endl;
    }
    cout<<":";
    */
    if(d[h-1][w-1]==INF) cout<<0<<endl;
    else cout<<d[h-1][w-1]<<endl;
  }
  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;

template<typename A, size_t N, typename T>
void static_fill(A (&arr)[N], const T &val){ fill((T*)arr, (T*)(arr+N), val); }

const int INF = 100000;
const int dy[] = {1, -1, 0, 0};
const int dx[] = {0, 0, 1, -1};

int w, h;
bool wall[31][31][31][31];
int d[31][31];

bool chmin(int &a, int b) {
    if (a <= b) return false;
    a = b;
    return true;
}

bool is_wall(int y1, int x1, int y2, int x2) {
    if (x2 < 0 || w <= x2 || y2 < 0 || h <= y2) return true;
    return wall[y1][x1][y2][x2];
}

void set_wall(int y1, int x1, int y2, int x2) {
    wall[y1][x1][y2][x2] = wall[y2][x2][y1][x1] = true;
}

int main() {
    while (cin >> w >> h) {
        if ( ! w) break;

        static_fill(wall, false);
        int v;
        for (int i=0; i<2*h-1; ++i) {
            if (i % 2 == 0) {
                for (int j=0; j<w-1; ++j) {
                    cin >> v;
                    if (v) set_wall(i/2, j, i/2, j+1);
                }
            } else {
                for (int j=0; j<w; ++j) {
                    cin >> v;
                    if (v) set_wall(i/2, j, i/2+1, j);
                }
            }
        }

        static_fill(d, INF);
        d[0][0] = 1;
        queue<pair<int,int>> q;
        q.push(make_pair(0, 0));
        while ( ! q.empty()) {
            int y = q.front().first;
            int x = q.front().second;
            q.pop();
            for (int i=0; i<4; ++i) {
                if (is_wall(y, x, y+dy[i], x+dx[i])) continue;
                if (chmin(d[y+dy[i]][x+dx[i]], d[y][x]+1)) {
                    q.push(make_pair(y+dy[i], x+dx[i]));
                }
            }
        }
        cout << (d[h-1][w-1] == INF ? 0 : d[h-1][w-1]) << endl;
    }
    return 0;
}