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 <map>
#include <set>
#include <vector>
#include <stack>
#include <queue>
#include <string>
#include <iostream>
#include <cstdlib>
#include <cstdio>
#define F(A, B) for(int A=0; A<B; A++)
using namespace std;

int w, h;
int Min[100][100];
int dir[100][100][4];
bool used[100][100];

enum COMPASS{
	NORTH=0,
	WEST,
	SOUTH,
	EAST
};

void rec(int y, int x, int sum){
	if(Min[y][x] <= sum)return;
	used[y][x] = true;
	if(y==h-1 && x==w-1){
		used[y][x] = false;
		if(Min[y][x] > sum){
			Min[y][x] = sum;
		}
		return;
	}

	if(x+1 < w && dir[y][x][EAST] == 1 && used[y][x+1] == false){
		rec(y, x+1, sum+1);
	}
	if(x-1 >= 0 && dir[y][x][WEST] == 1 && used[y][x-1] == false){
		rec(y, x-1, sum+1);
	}
	if(y-1 >= 0 && dir[y][x][NORTH] == 1 && used[y-1][x] == false){
		rec(y-1, x, sum+1);
	}
	if(y+1 < h && dir[y][x][SOUTH] == 1 && used[y+1][x] == false){
		rec(y+1, x, sum+1);
	}
	used[y][x] = false;
	return;
}

main(){
	while(1){
		F(i, 100)F(j, 100)Min[i][j]=1<<30;
		cin >> w >> h;
		if(w==0)break;
		F(i, 100)F(j, 100)F(k, 4)dir[i][j][k]=0;
		F(i, h)F(j, w)used[i][j]=false;
		F(i, h){
			F(j, w-1){
				int wall;
				cin >> wall;
				if(wall == 0){
					dir[i][j][EAST] = 1;
					dir[i][j+1][WEST] = 1;
				}
			}
			if(i == h-1)break;
			F(j, w){
				int wall;
				cin >> wall;
				if(wall == 0){
					dir[i][j][SOUTH] = 1;
					dir[i+1][j][NORTH] = 1;
				}
			}
		}
		rec(0, 0, 1);
		int ans = Min[h-1][w-1];
		if(ans == 1<<30)ans=0;
		cout << ans << endl;
	}
}

C++: #define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
#define rep(i, n) for(ll i = 0; i < (n); ++i)
#define FOR(i, m, n) for(ll i = m; i < (n); i++)
#define all(x) (x).begin(),(x).end()
using namespace std;
typedef long long ll;
using vi = vector<int>;
using vii = vector<vi>;
using pii = pair<int, int>; 
using vl = vector<ll>;
using vll = vector<vl>;
using pll = pair<ll, ll>;

const int dr[4] = {1, -1, 0, 0};
const int dc[4] = {0, 0, 1, -1};

int main() {
    while(true){
        ll w, h;
        cin >> w >> h;
        if(w == 0 && h == 0) return 0;
        vector<vector<bool>> wall_ver(w+1, vector<bool>(h, false)), wall_hori(h+1, vector<bool>(w, false));
        rep(i, h){
            wall_ver[0][i] = wall_ver[w][i] = true;
        }
        rep(i, w){
            wall_hori[0][i] = wall_hori[h][i] = true;
        }

        FOR(j, 1, w){
            ll f; cin>>f;
            if(f == 1) wall_ver[j][0] = true;
        }
        FOR(i, 1, h){
            rep(j, w){
                ll f; cin>>f;
                if(f == 1) wall_hori[i][j] = true;
            }
            FOR(j, 1, w){
                ll f; cin>>f;
                if(f == 1) wall_ver[j][i] = true;
            }
        }

        vll dist(h, vl(w, 0));
        queue<pll> q;
        dist[0][0] = 1;
        q.push(pll(0, 0));
        while(!q.empty()){
            pll v = q.front();
            q.pop();
            ll r = v.first, c = v.second;
            ll nr, nc;
            rep(i, 4){
                nr = r + dr[i], nc = c + dc[i];
                if(i == 0){
                    if(wall_hori[nr][c]) continue;
                }else if(i == 1){
                    if(wall_hori[r][c]) continue;
                }else if(i == 2){
                    if(wall_ver[nc][r]) continue;
                }else if(i == 3){
                    if(wall_ver[c][r]) continue;
                }
                if(dist[nr][nc] != 0) continue;

                dist[nr][nc] = dist[r][c] + 1;
                q.push(pll(nr, nc));
            }
        }

        cout << dist[h-1][w-1] << endl;
    }
}