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<cstdio>
#include<string>
#include<vector>
#include<cmath>
#include<algorithm>
#include<functional>
#include<iomanip>
#include<queue>
#include<ciso646>
#include<random>
#include<map>
#include<set>
using namespace std;
typedef long long ll;
const ll MOD = 1000000007;
const ll INF = (ll)1000000007 * 1000000007;
const double PI = 3.14159265358979;
const double E = 2.718281828459045;
const double root2 = sqrt(2);
typedef pair<int, int> P;
typedef unsigned int ui;
int main() {
	int w, h;
	while (cin >> w >> h,w) {
		int wall[100][100] = {};
		for (int i = 0; i <= 2 * w; i++) {
			wall[0][i] = 1;
			wall[2 * h][i] = 1;
		}
		for (int i = 0; i <= 2 * h; i++) {
			wall[i][0] = 1;
			wall[i][2 * w] = 1;
		}
		int c;
		for (int i = 1; i <= 2*h-1; i++){
			if (i % 2) {
				for (int j = 1; j <= w - 1; j++) {
					cin >> c;
					if (c)wall[i][2 * j] = 1;
				}
			}
			else {
				for (int j = 1; j <= w; j++) {
					cin >> c;
					if (c)wall[i][2 * j - 1] = 1;
				}
			}
		}
		vector<P> v; v.push_back({ 1,1});
		int d[100][100];
		for (int i = 0; i < 100; i++) {
			for (int j = 0; j < 100; j++) {
				d[i][j] = (int)MOD;
			}
		}
		d[1][1] = 1;
		while (!v.empty()) {
			int len = v.size();
			for (int i = 0; i < len; i++) {
				int x = v[0].first; int y = v[0].second; v.erase(v.begin());
				if (wall[x + 1][y] == 0) {
					if (d[x + 2][y] > d[x][y] + 1) {
						d[x + 2][y] = d[x][y] + 1;
						v.push_back({ x + 2,y });
					}
				}
				if (wall[x - 1][y] == 0) {
					if (d[x - 2][y] > d[x][y] + 1) {
						d[x - 2][y] = d[x][y] + 1;
						v.push_back({ x - 2,y });
					}
				}
				if (wall[x][y+1] == 0) {
					if (d[x][y+2] > d[x][y] + 1) {
						d[x][y+2] = d[x][y] + 1;
						v.push_back({ x,y+2 });
					}
				}
				if (wall[x][y-1] == 0) {
					if (d[x][y-2] > d[x][y] + 1) {
						d[x][y-2] = d[x][y] + 1;
						v.push_back({ x,y-2 });
					}
				}
			}
		}
		if (d[2 * h - 1][2 * w - 1] == (int)MOD)cout << 0 << endl;
		else cout << d[2 * h - 1][2 * w - 1] << endl;
	}
	return 0;
}

C++: #include<iostream>
#include<vector>
#include<queue>
#include<cstring>
using namespace std;

int memo[1024][1024];

int main() {
  for(;;) {
    int R, C;
    cin >> C >> R >> ws;
    if( C == 0 && R == 0 ) break;
    C = C * 2 - 1;
    R = R * 2 - 1;
    
    vector<string> vs;
    for(int i = 0; i < R; i++) {
      string line;
      getline(cin, line);
      line += " ";      
      vs.push_back(line);
    }
    
    memset(memo, -1, sizeof(memo));
    memo[0][0] = 1;
    
    queue<int> q;
    q.push(0);
    q.push(0);
    while( !q.empty() ) {
      int x = q.front(); q.pop();
      int y = q.front(); q.pop();
      
      const int dx[] = {0, 0, 1, -1};
      const int dy[] = {1, -1, 0, 0};
      
      for(int k = 0; k < 4; k++) {
        int nx = x + dx[k];
        int ny = y + dy[k];
        
        if( 0 <= nx && nx < R && 0 <= ny && ny < C ) {
          if( vs[nx][ny] == '0' ) {
            nx += dx[k];
            ny += dy[k];
            
            if( memo[nx][ny] == -1 ) {
              memo[nx][ny] = memo[x][y] + 1;
              q.push(nx);
              q.push(ny);
            }
            
          }
        }
        
      }
      
    }
    
    int res = memo[R - 1][C - 1];
    if( res == -1 ) res = 0;
    
    cout << res << endl;
  }

  return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
struct node{int x,y,c;}; 
int main(){
  int w,h;
  while(cin>>w>>h,w+h){
    vector<int> w1[33],w2[33];
    for(int i=0;i<h;i++){
      for(int j=0;j<w-1;j++){
	int a;
	cin>>a;
	w1[i].push_back(a);
      }
      w1[i].push_back(1);
      if(i==h-1){
	for(int j=0;j<w;j++)
	  w2[i].push_back(1);
      }else{
	for(int j=0;j<w;j++){
	  int a;
	  cin>>a;
	  w2[i].push_back(a);
	}
      }
    }
    int ma[33][33]={};
    queue<node> que;
    que.push((node){0,0,1});
    while(!que.empty()){
      int x=que.front().x;
      int y=que.front().y;
      int c=que.front().c;
      que.pop();
      if(ma[x][y])continue;
      ma[x][y]=c;
      if(w1[x][y]==0)que.push((node){x,y+1,c+1});
      if(w2[x][y]==0)que.push((node){x+1,y,c+1});
      if(y!=0&&w1[x][y-1]==0)que.push((node){x,y-1,c+1});
      if(x!=0&&w2[x-1][y]==0)que.push((node){x-1,y,c+1});
    }
    cout<<ma[h-1][w-1]<<endl;
  }
  return 0;
}