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<stdio.h>
#include<iostream>
#include<math.h>
#include<algorithm>
#include<string>
#define pi 3.14159
#define Inf 9999
using namespace std;



int w, h, a[59][59];
void dfs(int y, int x, int step);
int main(){
	while(1) {
		cin >> w >> h;
		if(w == 0 && h == 0) break;
		for(int i = 0; i < 2*h-1; i++) {
			for(int j = 0; j < 2*w-1; j++) {
				if(i % 2 == 0 && j % 2 == 0) a[i][j] = Inf;
				else if(i % 2 == 1 && j % 2 == 1) a[i][j] = Inf;
				else cin >> a[i][j];
			}
		}
		a[0][0] = 1;
		if(a[0][1] == 0) dfs(0, 2, 1);
		if(a[1][0] == 0) dfs(2, 0, 1);
		if(a[2*h-2][2*w-2] == Inf) cout << 0 <<endl;
		else cout << a[2*h-2][2*w-2] <<endl;
	}
	return 0;
}

void dfs(int y, int x, int step) {
	if(y < 0 || x < 0 || y >= 2*h-1 || x >= 2*w-1) return;
	if(step >= a[y][x]) return;
	else {
		step++;
		a[y][x] = step;
		if(x + 1 < 2*w-1) {
			if(a[y][x+1] == 0) dfs(y, x+2, step);
		}
		if(y+1 < 2*h-1) { 
			if(a[y+1][x] == 0) dfs(y+2, x, step);
		if(y - 1 >= 0) {
			if(a[y-1][x] == 0) dfs(y-2, x, step);
		}
		if(x - 1 >= 0) {
			if(a[y][x-1] == 0) dfs(y, x-2, step);
		}
	}
	return;
}

C++: #include <iostream>
#include <queue>
#define MAXN 30
#define MAXNN 900

using namespace std;

int solve(int a[MAXNN][MAXNN],int w,int h,int min[MAXNN]){
	int result=0;
	int sel;
	bool flg[MAXNN];

	for(int i=0;i<MAXNN;i++) flg[i]=false;
	
	queue<int> q;
	q.push(0);
	flg[0]=1;
	int dis=0;
	min[0]=dis;

	while(!q.empty()){
		sel=q.front();
		q.pop();
		for(int i=0;i<MAXNN;i++){
			if(flg[i]==0 && a[sel][i]==1){
				q.push(i);
				flg[i]=1;
				min[i]=min[sel]+1;
			}
		}
	}

	return min[(h-1)*MAXN+(w-1)]+1;
}

int main(void){
	int w,h,d;

	int a[MAXNN][MAXNN];
	int adX[2]={1,0};
	int adY[2]={0,1};
	int min[MAXNN];

	while(1){
		for(int i=0;i<MAXNN;i++){
			for(int j=0;j<MAXNN;j++)a[i][j]=0;
			min[i]=-1;
		}
		cin >> w;
		if(w==0) return 0;
		cin >> h;

		for(int y=0;y<h;y++){
			for(int x=0;x<w;x++){
				if((x+1)<w){
					a[y*MAXN+x][y*MAXN+x+1]=1;
					a[y*MAXN+x+1][y*MAXN+x]=1;
				}
				if((y+1)<h){
					a[y*MAXN+x][(y+1)*MAXN+x]=1;
					a[(y+1)*MAXN+x][y*MAXN+x]=1;
				}
			}
		}

		for(int y=0;y<2*h-1;y++){
			for(int x=0;x<w;x++){
				if(y%2==0){
					if(x==w-1) break;
					cin >> d;
					if(d==1){
						a[(y/2)*MAXN+x][(y/2)*MAXN+x+1]=0;
						a[(y/2)*MAXN+x+1][(y/2)*MAXN+x]=0;
					}
				}
				else{
					cin >> d;
					if(d==1){
						a[(y/2)*MAXN+x][((y/2)+1)*MAXN+x]=0;
						a[((y/2)+1)*MAXN+x][(y/2)*MAXN+x]=0;
					}
				}
			}
		}

		cout << solve(a,w,h,min) << endl;;
	}

	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
 
int dx[] = { 1, 0, -1, 0 };
int dy[] = { 0, -1, 0, 1 };
 
int main(void){
 
    int w, h;
 
    while (cin >> w >> h , w, h){
        bool x_wall[40][40] = { false }, y_wall[40][40] = { false };
        bool used[40][40];
        queue<pair <int, pair<int, int> > > que;
 
        for (int j = 0; j < h; j++){
            for (int i = 0; i < w; i++) used[j][i] = false;
        }
 
        for (int i = 0; i < w; i++) y_wall[0][i] = true;
         
        for (int j = 0; j < h - 1; j++){
            int buff;
            x_wall[j][0] = true;
            for (int i = 1; i < w; i++) cin >> x_wall[j][i];
            x_wall[j][w] = true;
 
            for (int i = 0; i < w; i++) cin >> y_wall[j + 1][i];
             
        }
 
        x_wall[h-1][0] = true;
        for (int i = 1; i < w; i++) cin >> x_wall[h-1][i];
        x_wall[h-1][w] = true;
 
        for (int i = 0; i < w; i++) y_wall[h][i] = true;
 
        que.push(make_pair(1, make_pair(0, 0)));
 
        bool flag = false;
 
        while (!que.empty()){
            pair <int, pair<int, int> > nxy = que.front();
            que.pop();
 
            int x = nxy.second.first;
            int y = nxy.second.second;
            if (used[y][x] || x < 0 || w < x || y < 0 || h < y)continue;
 
            used[y][x] = true;
 
            if (x == w - 1 && y == h - 1){
                cout << nxy.first << endl;
                flag = true;
                while (!que.empty()) que.pop();
                break;
            }

 
            if (!x_wall[y][x] && !used[y][x - 1]) que.push(make_pair(nxy.first + 1, make_pair(x - 1, y)));
            if (!y_wall[y][x] && !used[y - 1][x]) que.push(make_pair(nxy.first + 1, make_pair(x, y - 1)));
            if (!x_wall[y][x + 1] && !used[y][x + 1]) que.push(make_pair(nxy.first + 1, make_pair(x + 1, y)));
            if (!y_wall[y + 1][x] && !used[y + 1][x]) que.push(make_pair(nxy.first + 1, make_pair(x, y + 1)));
 
        }
 
        if (!flag) cout << 0 << endl;
 
    }
 
    return 0;
}