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 MAX 30
#define INFTY 901

std::map<char,int> create_map() {
    std::map<char, int> m;
    m.insert({'L', 0});
    m.insert({'U', 1});
    m.insert({'R', 2});
    m.insert({'D', 3});
    return m;
};
static std::map<char, int> m = create_map();

class square {
public:
    bool walls[4];
    square() {
        std::memset(walls, false, sizeof(walls));
    }
    void setWall(char d) {
        walls[m[d]] = true;
    }
    void reset() {
        std::memset(walls, false, sizeof(walls));
    }
};
int W, H, sx, sy, gx, gy;
square map[MAX][MAX];
int d[MAX][MAX];
static int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
static char dirs[4] = {'D', 'R', 'U', 'L'};

int bfs() {
    std::queue< std::pair<int, int> > Q;

    for (int i = 0; i < H; i++) {
        for (int j = 0; j < W; j++) d[i][j] = INFTY;
    }

    Q.push({sx, sy});

    d[sx][sy] = 1;
    int nx, ny, dir;
    while (Q.size()) {
        std::pair<int, int> p = Q.front(); Q.pop();

        if (p.first == gx && p.second == gy) break;

        for (int i = 0; i < 4; i++) {
            dir = m[dirs[i]];
            nx = p.first + dx[i], ny = p.second + dy[i];
            if (0 <= nx && nx < H && 0 <= ny && ny < W && d[nx][ny] == INFTY && !map[p.first][p.second].walls[dir]) {
                Q.push({nx, ny});
                d[nx][ny] = d[p.first][p.second] + 1;
            }
        }
    }
    return d[gx][gy];
}


int main()
{

    int tmp;

    while (1) {

        std::scanf("%d %d", &W, &H);
        if (W == 0 && H == 0) break;

        for (int i = 0; i < H; i++) {
            for (int j = 0; j < W; j++) map[i][j].reset();
        }

        for (int i = 0; i < H; i++) {
            //vertical set
            for (int j = 0; j < W-1; j++) {
                std::scanf("%d", &tmp);
                if (tmp == 1) {
                    map[i][j+1].setWall('L');
                    map[i][j].setWall('R');
                }
            }
            if (i == H-1) break;
            //horizontal set
            for (int j = 0; j < W; j++) {
                std::scanf("%d", &tmp);
                if (tmp == 1) {
                    map[i][j].setWall('D');
                    map[i+1][j].setWall('U');
                }
            }
        }

        sx = sy = 0;
        gx = H-1, gy = W-1;

        int res = bfs();

        (res == INFTY) ? std::printf("%d\n", 0) : std::printf("%d\n", res);

    }

    return 0;
}

C++: #include <bits/stdc++.h>
#define rep(i, a, n) for(int i = a; i < n; i++)
#define repb(i, a, b) for(int i = a; i >= b; i--)
#define all(a) a.begin(), a.end()
#define int long long
using namespace std;
typedef pair<int, int> P;

const int INF = 1e8;

int dy[4] = {1, -1, 0, 0};
int dx[4] = {0, 0, 1, -1};

signed main(){
    int w, h;
    while(1){
        cin >> w >> h;
        if(w + h == 0) break;
        int wally[30][30];
        int wallx[30][30];
        rep(i, 0, 2*h - 1){
            if(i % 2 == 0){
                rep(j, 0, w - 1){
                    cin >> wally[i / 2][j];
                }
            }else{
                rep(j, 0, w){
                    cin >> wallx[i / 2][j];
                }
            }
        }
        queue<P> q;
        int y = 0, x = 0;
        q.push(P(y, x));
        int d[31][31];
        rep(i, 0, 31) rep(j, 0, 31) d[i][j] = INF;
        d[0][0] = 1;

        while(q.size()){
            P now = q.front(); q.pop();
            if(now. first == h - 1 && now . second == w - 1) break;
            rep(i, 0, 4){
                int ny = now. first + dy[i];
                int nx = now. second + dx[i];
                if(ny < 0 || h <= ny || nx < 0 || w <= nx) continue;
                if(d[ny][nx] != INF) continue;
                if(i == 0 && wallx[now. first][nx]) continue;
                if(i == 1 && wallx[now. first][nx]) continue;
                if(i == 2 && wally[ny][now. second]) continue;
                if(i == 3 && wally[ny][nx]) continue;
                d[ny][nx] = d[now. first][now. second] + 1;
                q.push(P(ny, nx));   
            }
        }
        cout << (d[h - 1][w - 1] == INF ? 0 : d[h - 1][w - 1]) << endl;
    }
}