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++: #define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <cstdio>
#include <cmath>
#include <queue>
#include <utility>
#include <cstring>
using namespace std;

#define INF 10000
#define TEST 0
#if TEST
FILE* in = freopen("./B.txt", "r", stdin);
FILE* out = freopen("./ans.txt", "w", stdout);
#endif

int w, h;
bool ok;
bool barrier[2][31][31];
int cost[31][31];

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

inline bool isRegion(int x, int y){
    return x >= 0 && x < w && y >= 0 && y < h;
}

void bfs(){
    queue<pair<int,int>> q;
    q.push(make_pair(0,0));
    
    while(!q.empty()){
        int x = q.front().first;
        int y = q.front().second;
        q.pop();
        cost[x][y] = INF;
        if(!x && !y) cost[x][y] = 1;
        
        for(int i = 0; i < 4; i++){
            int nx = x + dx[i], ny = y + dy[i];
            
            int isV = (i+1) & 1;
            int minX = min(x, nx), minY = min(y, ny);
            if(isRegion(nx, ny) && !barrier[isV][minX][minY]){
                if(cost[nx][ny]){
                    cost[x][y] = min(cost[x][y], cost[nx][ny] + 1);
                } else {
                    q.push(make_pair(nx, ny));
                }
            }
            
        }
        
    }
}

int main(int argc, const char * argv[]) {
    cin.tie(0);
    ios::sync_with_stdio(false);
    
    while(1){
        cin >> w >> h;
        if(!w && !h) break;
        
        ok = false;
        memset(barrier, 0, sizeof(barrier));
        memset(cost, 0, sizeof(cost));
        
        for(int y = 0; y < h; y++){
            for(int x = 0; x < w - 1; x++){
                cin >> barrier[0][x][y];
            }
            
            if(y != h-1){
                for(int x = 0; x < w; x++){
                    cin >> barrier[1][x][y];
                }
            }
        }
        
        bfs();
        cout << cost[w-1][h-1] << endl;
    }
#if TEST
    fclose(in);
    fclose(out);
#endif
}

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

#define dump(x) cout << (x) << '\n'
#define Int int64_t
#define fi first
#define se second
#define all(x) (x).begin(), (x).end()

Int INF = 1e18;
int inf = 1e9;
Int mod = 1e9+7;

int d[100][100];

int main() {
    vector<int> res;
    while (true) {
        int h, w;
        cin >> w >> h;
        if (h == 0) break;
        map<pair<pair<int, int>, pair<int, int>>, int> mp;
        for (int i = 0; i < 2 * h - 1; i++) {
            if (i % 2 == 0) {
                for (int j = 0; j < w - 1; j++) {
                    int x;
                    cin >> x;
                    if (x == 1) {
                        mp[{{i / 2, j}, {i / 2, j + 1}}]++;
                        mp[{{i / 2, j + 1}, {i / 2, j}}]++;
                    }
                }
            }
            else {
                for (int j = 0; j < w; j++) {
                    int x;
                    cin >> x;
                    if (x == 1) {
                        mp[{{i / 2, j}, {i / 2 + 1, j}}]++;
                        mp[{{i / 2 + 1, j}, {i / 2, j}}]++;
                    }
                }
            }
        }
        for (int i = 0; i < h; i++) {
            for (int j = 0; j < w; j++) {
                d[i][j] = inf;
            }
        }
        d[0][0] = 1;
        queue<pair<int, int>> q;
        q.push({0, 0});
        while (not q.empty()) {
            pair<int, int> p = q.front();
            q.pop();
            int dx[] = {1, 0, -1, 0};
            int dy[] = {0, -1, 0, 1};
            for (int i = 0; i < 4; i++) {
                int ny = p.fi + dy[i];
                int nx = p.se + dx[i];
                if (ny < 0 or ny == h or nx < 0 or nx == w) continue;
                if (mp[{p, {ny, nx}}] > 0) continue;
                if (d[ny][nx] > d[p.fi][p.se] + 1) {
                    d[ny][nx] = d[p.fi][p.se] + 1;
                    q.push({ny, nx});
                }
            }
        }
        // for (int i = 0; i < h; i++) {
        //     for (int j = 0; j < w; j++) {
        //         cout << d[i][j] << " " ;
        //     }
        //     cout << endl;
        // }
        res.emplace_back(d[h - 1][w - 1] == inf ? 0 : d[h - 1][w - 1]);
    }
    for (int i = 0; i < (int)res.size(); i++) {
        dump(res[i]);
    }
    return 0;
}