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 <cstdlib>
#include <queue>
#include <set>
#include <map>

using namespace std;

struct state {
  pair< int, int > pos;
  int steps;
  state( pair<int, int>pos, int steps) {
    this->pos = pos;
    this->steps = steps;
  }
};

int main() {
  while( 1 ) {
    bool vw[ 35 ][ 35 ];
    bool hw[ 35 ][ 35 ];

    int w, h;
    cin >> w >> h;
    if( !w && !h ) {
      break;
    }
    for( int j = 0; j <= w; j++ ) {
      hw[ h ][ j ] = true;
      hw[ 0 ][ j ] = true;
    }
    for( int i = 0; i < h; i++ ) {
      // v
      vw[ i ][ 0 ] = true;
      for( int j = 1; j < w; j++ ) {
        cin >> vw[ i ][ j ]; // false: 0, true: other
      }
      vw[ i ][ w ] = true;

      // h
      if( i != h - 1 ) {
        for( int j = 0; j < w; j++ ) {
          cin >> hw[ i + 1 ][ j ];
        }
      }
    }
    
    queue< state > q;
    set< pair<int, int> > s;
    q.push( state( pair<int,int>( 0, 0 ), 0 ) );
    int ans = 0;
    while( !q.empty() ) {
      state st = q.front();
      q.pop();
      if( s.find( st.pos ) != s.end() ) {
        continue;
      }
      s.insert( st.pos );

      int i = st.pos.first;
      int j = st.pos.second;
      cout << i << " " <<  j << " " << st.steps <<  endl;
      if( i == h - 1 && j == w - 1 ) {
        ans = st.steps + 1;
        break;
      }

      // up
      if( !hw[ i ][ j ] ) {
        q.push( state( pair<int,int>( i - 1, j ), st.steps + 1 ) );
      }

      // down
      if( !hw[ i + 1 ][ j ] ) {
        q.push( state( pair<int,int>( i + 1, j ), st.steps + 1 ) );
      }

      // left
      if( !vw[ i ][ j ] ) {
        q.push( state( pair<int,int>( i, j - 1 ), st.steps + 1 ) );
      }

      // right
      if( !vw[ i ][ j + 1 ] ) {
        q.push( state( pair<int,int>( i, j + 1 ), st.steps + 1 ) );
      }

    }

    cout << ans << endl;
  }

  return EXIT_SUCCESS;
}

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

typedef pair<int,int> P;
typedef pair<int,pair<int,int>> PP;
int main(){
	for(int w,h;;){
		cin>>w>>h;
		if(w+h==0)break;
		vector<vector<vector<P>>> g(w,vector<vector<P>>(h,vector<P>()));
		for(int d,i=1; i<=h; i++){
			for(int j=1; j<w; j++){
				cin>>d;
				if(!d){
					g[j-1][i-1].push_back(P(1,0));
					g[j][i-1].push_back(P(-1,0));
				}
			}
			if(i!=h){
				for(int j=0; j<w; j++){
					cin>>d;
					if(!d){
						g[j][i-1].push_back(P(0,1));
						g[j][i].push_back(P(0,-1));
					}
				}
			}
		}
		/*
		for(int i=0; i<h; i++){
			for(int j=0; j<w; j++){
				cout<<g[j][i].size()<<" ";
			}
			cout<<endl;
		}
		*/
		vector<vector<int>> d(w,vector<int>(h,INT_MAX));
		priority_queue<PP, vector<PP>, greater<PP>> q;
		q.push(PP(d[0][0]=1,P(0,0)));
		for(;q.size();){
			int cost = q.top().first;
			P now = q.top().second;
			q.pop();
			for(P v : g[now.first][now.second]){
				v.first += now.first;
				v.second += now.second;
				if(cost+1 < d[v.first][v.second]){
					q.push(PP(d[v.first][v.second]=cost+1,v));
				}
			}
		}
		cout<<(d[w-1][h-1] < INT_MAX ? d[w-1][h-1] : 0)<<endl;
	}
}