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 <queue>
#include <cstdio>

using namespace std;

struct Node {
	int x, y, step;
};

int main() {
	int w, h;
	while ( cin >> w >> h, getchar(), w || h ) {
		w = w * 2 - 1, h = h * 2 - 1;
		int m[100][100] = {0};
		for (int y = 0; y < h; ++y) {
			string str; getline(cin, str);
			for (int x = 0; x < str.size(); ++x) {
				if ( str[x] == '1' ) m[y][x] = 1;
			}
		}
		for (int y = 1; y < h; y += 2) {
			for (int x = 1; x < w; x += 2) {
				m[y][x] = 1;
			}
		}
		/*
		for (int y = 0; y < h; ++y) {
			for (int x = 0; x < w; ++x) {
				cout << m[y][x];
			}
			cout << endl;
		}
		*/
		int ans = 0;
		bool gone[100][100] = {0};
		queue<Node> Q; Q.push( (Node){0, 0, 0} );
		while ( !Q.empty() ) {
			Node node = Q.front(); Q.pop();
			int x = node.x, y = node.y, step = node.step;
			if (x < 0 || x >= w || y < 0 || y >= h) continue;

			if (m[y][x]) continue;
			if (gone[y][x]) continue;
			gone[y][x] = true;

			if (x == w-1 && y == h-1) {
				ans = step/2 + 1;
				break;
			}

			Q.push( (Node){x+1, y, step+1} );
			Q.push( (Node){x-1, y, step+1} );
			Q.push( (Node){x, y+1, step+1} );
			Q.push( (Node){x, y-1, step+1} );
		}
		cout << ans << endl;
	}
}

C++: #include<iostream>
#include<iomanip>
#include<cmath>
#include<string>
#include<vector>
#include<algorithm>
#include<map>
#include<queue>
#include<stack>
using namespace std;
typedef long long ll;
#define fi first
#define se second
const int inf=1e9+7;
const ll mod=1e9+7;

int main() {
    vector<int> ansarr;
    int W, H;
    while(true){
        cin>>W>>H;
        if((W==0) & (H==0))break;
        vector<vector<int> > kabe(2*H-1);
        int tmp;
        for(int i=0;i<2*H-1;++i){
            if(i%2==0){
                for(int j=0;j<W-1;++j){
                    cin>>tmp;
                    kabe[i].push_back(tmp);
                }
            }
            else{
                for(int j=0;j<W;++j){
                    cin>>tmp;
                    kabe[i].push_back(tmp);
                }
            }
        }
        queue<pair<int, int> > que;
        queue<int> numque;
        pair<int, int> state;
        map<pair<int, int>, int> past;
        int num;
        que.push(make_pair(0, 0));
        numque.push(1);
        int ans = 0;
        int x, y;
        while(!que.empty()){
            state = que.front();que.pop();
            num = numque.front();numque.pop();
            x = state.se;
            y = state.fi;
            if((x==W-1) & (y==H-1)){
                ans = num;
                break;
            }
            if(past[make_pair(y, x)]>0)continue;
            past[make_pair(y, x)] = 1;
            if(x-1>=0){
                if((kabe[2*y][x-1]==0) & (past[make_pair(y, x-1)]==0)){
                    que.push(make_pair(y, x-1));
                    numque.push(num+1);
                }
            }
            if(x+1<W){
                if((kabe[2*y][x]==0) & (past[make_pair(y, x+1)]==0)){
                    que.push(make_pair(y, x+1));
                    numque.push(num+1);
                }
            }
            if(y-1>=0){
                if((kabe[2*y-1][x]==0) & (past[make_pair(y-1, x)]==0)){
                    que.push(make_pair(y-1, x));
                    numque.push(num+1);
                }
            }
            if(y+1<H){
                if((kabe[2*y+1][x]==0) & (past[make_pair(y+1, x)]==0)){
                    que.push(make_pair(y+1, x));
                    numque.push(num+1);
                }
            }
        }
        ansarr.push_back(ans);
    }
    for(int i=0;i<ansarr.size();++i){
        cout<<ansarr[i]<<endl;
    }
}