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 <string>
#include <algorithm>
#include <cstring>
#include <vector>
#include <map>
#include <queue>
using namespace std;
typedef pair<int,int> P;
#define mp make_pair

int W, H;
int dist[30][30];
const int dy[4] = {-1, 0, 1, 0};
const int dx[4] = {0, 1, 0, -1};

int main (int argc, char const* argv[]) {
  while (true) {
    cin >> W >> H;
    cin.ignore();
    if (W == 0 && H == 0) break;
    
    vector<string> wall(2 * H - 1);
    for (int i=0;i<2*H-1;i++) getline(cin, wall[i]);
    memset(dist, -1, sizeof dist);
    
    queue<pair<int,P> > que;
    que.push(mp(1,mp(0,0)));
    bool goal_flag = false;
    while (!que.empty()) {
      pair<int,P> p = que.front(); que.pop();
      int x = p.second.first;
      int y = p.second.second;
      int d = p.first;
      if (dist[y][x] != -1) continue;
      dist[y][x] = d;
      if (x == W-1 && y == H-1) {
        cout << d << endl;
        goal_flag = true;
        break;
      }
      // right
      if (x+1 < W && wall[2*y][2*x+1] == '0' && dist[y][x+1] == -1) {
        que.push(mp(d+1,mp(x+1,y)));
      }
      // down
      if (y+1 < H && wall[2*y+1][2*x] == '0' && dist[y+1][x] == -1) {
        que.push(mp(d+1,mp(x,y+1)));
      }
      // up
      if (y-1 >= 0 && wall[2*y-1][2*x] == '0' && dist[y-1][x] == -1) {
        que.push(mp(d+1,mp(x,y-1)));
      }
      // left
      if (x-1 >= 0 && wall[2*y][2*x-1] == '0' && dist[y][x-1] == -1) {
        que.push(mp(d+1,mp(x-1,y)));
      }
    }
    if (!goal_flag) {
      cout << 0 << endl;
    }
  }
  return 0;
}

C++: #include <iostream>
#include <cstring>

#define INF 1e9

using namespace std;
int w,h;
int wr[32][32];
int wb[32][32];
int dp[32][32];
int v[32][32];

void solve(){
	int x,y,i,j;
	x=0;y=0;
	while(1){
		v[x][y] = 1;
		if(x==w-1 && y==h-1) return;

		if(!wr[y][x  ]) dp[x+1][y] = min(dp[x+1][y], dp[x][y]+1);
		if(!wr[y][x-1] && x) dp[x-1][y] = min(dp[x-1][y], dp[x][y]+1);
		if(!wb[y][x  ]) dp[x][y+1] = min(dp[x][y+1], dp[x][y]+1);
		if(!wb[y-1][x] && y) dp[x][y-1] = min(dp[x][y-1], dp[x][y]+1);
		
		x=w-1;y=h-1;
		for(i=0;i<h;i++)
			for(j=0;j<w;j++){
				if(dp[j][i] == INF || v[j][i]) continue;
				if(dp[j][i] < dp[x][y]){
					x=j,y=i;
				}
			}
		if(v[x][y] || dp[x][y] == INF) return;
	}
}

main(){
	int i,j;
	while(cin>>w>>h, w){
		memset(v, 0, sizeof(v));
		memset(dp, 0, sizeof(dp));
		for(i=0;i<=h;i++)
			for(j=0;j<=w;j++)
				dp[j][i] = INF;
		for(i=0;i<h-1;i++){
			for(j=0;j<w-1;j++){
				cin >> wr[i][j];
			}
			for(j=0;j<w;j++){
				cin >> wb[i][j];
			}
		}
		for(j=0;j<w-1;j++){
			cin >> wr[i][j];
		}
		dp[0][0] = 1;
		solve();
		if(dp[w-1][h-1] != INF) cout << dp[w-1][h-1] << endl;
		else cout << 0 << endl;
	}
}

C++: #include <bits/stdc++.h>
#include <math.h>

using namespace std;

long long inf=1000000007;

long long modpow(long long n,long long p,long long mod);

int main(){
	long long w,h;
	cin>>w>>h;

	while(w!=0 || h!=0){
		struct mass{
			long long up=1;
			long long down=1;
			long long right=1;
			long long left=1;
		};

		vector<vector<mass>> grid(h,vector<mass>(w));

		for(long long i=0;i<h*2-1;i++){
			if(i%2==0){
				for(long long j=1;j<=w-1;j++){
					long long hoge;
					cin>>hoge;
					grid.at(i/2).at(j-1).right=hoge;
					grid.at(i/2).at(j).left=hoge;
				}
			}else{
				for(long long j=0;j<w;j++){
					long long hoge;
					cin>>hoge;
					grid.at(i/2).at(j).down=hoge;
					grid.at(i/2+1).at(j).up=hoge;
				}
			}
		}

		//TANSAKU START

		vector<vector<long long>> dis(h,vector<long long>(w,-1));
		queue<pair<long long,long long>> que;
		dis.at(0).at(0)=0;
		que.push(make_pair(0,0));

		while(!que.empty()){
			long long y=que.front().first;
			long long x=que.front().second;
			if(y==h-1 && x==w-1){
				break;
			}
			que.pop();

			if(grid.at(y).at(x).up==0 && dis.at(y-1).at(x)==-1){
				que.push(make_pair(y-1,x));
				dis.at(y-1).at(x)=dis.at(y).at(x)+1;
			}

			if(grid.at(y).at(x).down==0 && dis.at(y+1).at(x)==-1){
				que.push(make_pair(y+1,x));
				dis.at(y+1).at(x)=dis.at(y).at(x)+1;
			}

			if(grid.at(y).at(x).right==0 && dis.at(y).at(x+1)==-1){
				que.push(make_pair(y,x+1));
				dis.at(y).at(x+1)=dis.at(y).at(x)+1;
			}

			if(grid.at(y).at(x).left==0 && dis.at(y).at(x-1)==-1){
				que.push(make_pair(y,x-1));
				dis.at(y).at(x-1)=dis.at(y).at(x)+1;
			}
		}
		cout<<dis.at(h-1).at(w-1)+1<<endl;

		cin>>w>>h;
	}

	return 0;
}

long long modpow(long long n,long long p,long long mod){
	if(p==0) return 1;
	if(p%2==0) return (modpow(n,p/2,mod)*modpow(n,p/2,mod))%mod;
	if(p%2==1) return (modpow(n,p-1,mod)*n)%mod;
	cerr<<"ERROR"<<endl;
	return 1;
}