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>

#define inRange(x, y, w, h) (0 <= x && x < w && 0 <= y && y < h)

using namespace std;

struct Point {
	int x;
	int y;
	int count;
};

int main( void )
{
	int dx[] = { 0, 0, -1, 1 };
	int dy[] = { -1, 1, 0, 0 };
	int w, h;
	int map[60][60];
	while(cin >> w >> h, w | h) {
		w = 2 * w - 1; h = 2 * h - 1;
		for(int y=0; y < h; ++y)
			for(int x=0; x < w; ++x) map[y][x] = 9999;
		for(int y=0; y < h; ++y) {
			int input;
			for(int x=(y+1)%2; x < w; x+=2) { cin >> input; map[y][x] = (input)? 0 : 9999; }
		}
		for(int y=1; y < h; y+=2)
			for(int x=1; x < w; x+=2) {
				for(int d=0; d < 4; ++d) {
					int mx = x + dx[d];
					int my = y + dy[d];
					if(inRange(mx, my, w, h) && !map[my][mx]) {
						map[y][x] = 0;
						break;
					}
				}
			}

		Point tmp;
		queue<Point> q;
		tmp.x = tmp.y = 0; tmp.count = map[0][0] = 1;
		q.push(tmp);
		while(!q.empty()) {
			tmp = q.front(); q.pop();
			for(int d=0; d < 4; ++d) {
				int mx = tmp.x + dx[d];
				int my = tmp.y + dy[d];
				if(inRange(mx, my, w, h) && tmp.count+1 < map[my][mx]) {
					Point tmp2;
					tmp2.x = mx;
					tmp2.y = my;
					tmp2.count = map[my][mx] = tmp.count + 1;
					q.push(tmp2);
				}
			}
		}
		int answer = 0;
		if(map[h-1][w-1] != 9999)
			answer = (map[h-1][w-1] + 1) / 2;
		cout << answer << endl;
	}
	return 0;
}

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

using namespace std;

typedef unsigned long long ull;

#define loop(i,a,b) for(int i=(a);i<ull(b);++i)
#define rep(i,n) loop(i,0,n)

const double eps = 1e-10;
const double pi  = acos(-1.0);
const double inf = (int)1e8;

int field[100][100];
int cost[100][100];
int n, m;

int main(){
    while(cin >> n >> m, n+m){
        rep(i, 100)rep(j, 100) cost[i][j] = inf;

        for(int i=0; i< m*2-1; i++){
            for(int j=0; j < n; j++){
                if(i%2==0 && j == n-1) break;
                if(i%2==0) cin >> field[i][j*2+1];
                else cin >> field[i][j*2];
            }
        }
        queue<pair<int, int> >que;
        que.push(make_pair(0, 0));
        cost[0][0] = 0;

        while(que.size()){
            pair<int, int> p = que.front(); que.pop();
            if(p.first == m*2-2 && p.second == n*2-2) break;
            int dx[4] = {1, 0, -1, 0};
            int dy[4] = {0, 1, 0, -1};
            for(int i=0; i < 4; i++){
                if(0 <= p.first+dx[i]*2 && p.first+dx[i] < m*2-1 && 0 <= p.second+dy[i]*2 && p.second+dy[i] < n*2-1 && field[p.first+dx[i]*2][p.second+dy[i]] != 1 && field[p.first+dx[i]][p.second+dy[i]*2] != 1 && cost[p.first+dx[i]*2][p.second+dy[i]*2] == inf){
                    que.push(make_pair(p.first+dx[i]*2, p.second+dy[i]*2));
                    cost[p.first+dx[i]*2][p.second+dy[i]*2] = cost[p.first][p.second]+1;
                }
            }
        }
        int ret = cost[m*2-2][n*2-2];
        cout << (ret==inf?0:ret+1) << endl;
    }
}

C++: #include <iostream>
#include <queue>
#include <algorithm>
#define  INF  1000000
using namespace std;
struct edge{int to,cost;};
typedef pair <int ,int> P;
typedef vector<edge> graph;

graph g[910];

void ae(int from,int to,int cost){ 
	edge in1,in2;
	in1.to=to,in2.to=from;
	in1.cost=in2.cost=cost?10000:1;
	g[from].push_back(in1);
	g[to].push_back(in2);
}

int w,h;

int main(void){
	while(cin >> w >> h,w|h){
		/*for(int i=0;i<w*h;i++){
			cout << i << " "  ;
			for(int j=0;j<g[i].size();j++){
				cout << g[i][j].to << " ";
			}
			cout << endl;
		}*/
		for(int i=0;i<2*h-1;i++){
			if(i%2){//縦
				for(int j=0;j<w;j++){
					int tmp; cin >> tmp;
					ae(j+w*(i/2),j+w*(i/2)+w,tmp);
				}
			}else{//横
				for(int j=0;j<w-1;j++){
					int tmp; cin >> tmp;
					ae(j+i/2*w,j+i/2*w+1,tmp);
				}
			}
		}
		int d[910];
		priority_queue < P,vector<P>,greater<P> > q;
		fill(d,d+w*h,INF);
		d[0]=0;
		q.push(P(0,0));
		while(!q.empty()){
			P p=q.top();q.pop();
			int v=p.second;
			if(d[v]<p.first)
				continue;
			for(int i=0;i<g[v].size();i++){
				edge e=g[v][i];
				if(d[e.to]>d[v]+e.cost)
					d[e.to]=d[v]+e.cost,q.push(P(d[e.to],e.to));
			}	
		}
		if(d[w*h-1]>=10000)
			cout << 0 << endl;
		else 
			cout << d[w*h-1]+1 << endl;

		for(int i=0;i<910;i++)
			for(int j=0;j<g[i].size();)
				g[i].pop_back();
		/*for(int i=0;i<w*h;i++){
			cout << i << " "  ;
			for(int j=0;j<g[i].size();j++){
				cout << g[i][j].to << " ";
			}
			cout << endl;
		}*/
	}
	return 0;
}