Go: package main

import (
	"fmt"
	"math"
)

type Position struct {
	X int64
	Y int64
}

func (one Position) Distance(another Position) int64 {
	return int64(math.Abs(float64(one.X-another.X)) + math.Abs(float64(one.Y-another.Y)))
}

type PersonPosition struct {
	Takayuki Position
	Kazuyuki Position
}

func (one PersonPosition) Distance() int64 {
	return one.Takayuki.Distance(one.Kazuyuki)
}

type Status struct {
	Person PersonPosition
	Turn   int64
}

type PQStatus []*Status

func solve(h, w int64) {
	var tx, ty, kx, ky int64
	fmt.Scan(&tx, &ty, &kx, &ky)
	tx--
	ty--
	kx--
	ky--
	m := make([][]int64, h)
	for i := range m {
		m[i] = make([]int64, w)
		for j := int64(0); j < w; j++ {
			fmt.Scan(&m[i][j])
		}
	}
	start := &Status{Person: PersonPosition{Takayuki: Position{X: tx, Y: ty}, Kazuyuki: Position{X: kx, Y: ky}}, Turn: 0}
	pq := make(PQStatus, 0)
	pq = append(pq, start)
	dx := []int64{0, 1, 0, -1}
	dy := []int64{1, 0, -1, 0}
	memo := make(map[PersonPosition]int64, 0)
	ans := int64(102)
	for len(pq) > 0 {
		now := &Status{}
		*now = *pq[0]
		pq = pq[1:]
		if now.Person.Distance() == 0 && ans > now.Turn {
			ans = now.Turn
		}
		if ans <= now.Turn {
			continue
		}

		if _, ok := memo[now.Person]; ok {
			continue
		}
		memo[now.Person] = now.Turn

		for i := 0; i < 4; i++ {
			next := &Status{}
			*next = *now
			next.Person.Kazuyuki.X += dx[i]
			next.Person.Kazuyuki.Y += dy[i]
			if next.Person.Kazuyuki.X < 0 || next.Person.Kazuyuki.X >= w ||
				next.Person.Kazuyuki.Y < 0 || next.Person.Kazuyuki.Y >= h ||
				m[next.Person.Kazuyuki.Y][next.Person.Kazuyuki.X] == 1 {
				next.Person.Kazuyuki.X -= dx[i]
				next.Person.Kazuyuki.Y -= dy[i]
			}
			next.Person.Takayuki.X -= dx[i]
			next.Person.Takayuki.Y -= dy[i]
			if next.Person.Takayuki.X < 0 || next.Person.Takayuki.X >= w ||
				next.Person.Takayuki.Y < 0 || next.Person.Takayuki.Y >= h ||
				m[next.Person.Takayuki.Y][next.Person.Takayuki.X] == 1 {
				next.Person.Takayuki.X += dx[i]
				next.Person.Takayuki.Y += dy[i]
			}
			next.Turn++
			if next.Turn <= 100 {
				pq = append(pq, next)
			}
		}
	}
	if ans == 102 {
		fmt.Println("NA")
	} else {
		fmt.Println(ans)
	}
}

func main() {
	var h, w int64
	for {
		fmt.Scan(&h, &w)
		if h == 0 && w == 0 {
			break
		}
		solve(h, w)
	}
}

C++: /*??£?¨?*/
#include<cstdio>
#include<iostream>
#include<algorithm>
#include<math.h>
#include<queue>
#include<string.h>
#include<string>
#include<vector>
using namespace std;
#define rep(i,n) for(int i=0;i<n;i++)
#define rep1(i,n) for(int i=1;i<=n;i++)
struct X
{
	int tx, ty, t, kx, ky;
};
int java[51][51][51][51] = { 0 };
int main()
{
	int w, h, map[52][52] = { 0 };
		int mx[4] = { 0,1,0,-1 }, my[4] = { 1,0,-1,0 };
		while (1)
		{
			queue<X> que;
			X c;
			cin >> w >> h;
			if (w == 0 && h == 0)
				break;
			memset(java, 0, sizeof(java));
			cin >> c.tx >> c.ty >> c.kx >> c.ky;
			c.t = 0;
			que.push(c);
			rep1(i, h)
			{
				rep(j, w)
				{
					cin >> map[i][j];
				}
			}
			/*?£???????*/
			rep(i, h + 2)	//n???????????°,m????¨??????°
			{
				map[i][0] = 1;
				map[i][w + 1] = 1;
			}
			rep(i, w + 2)
			{
				map[0][i] = 1;
				map[h + 1][i] = 1;
			}
			while (1)
			{
				c = que.front();
				que.pop();
				java[c.tx][c.ty][c.kx][c.ky] = 1;
				if (c.tx == c.kx&&c.ty == c.ky&&c.t >= 100)
				{
					cout << "FACKYOU!" << endl;
					break;
				}
				c.t++;
				rep(i, 4)
				{
					if (java[c.tx + mx[i]][c.ty + my[i]][c.kx - mx[i]][c.ky - my[i]] == 0 && map[c.tx + mx[i]][c.ty + my[i]] == 0 && map[c.kx - mx[i]][c.ky - my[i]] == 0)
					{
						c.tx += mx[i];
						c.ty += my[i];
						c.kx -= mx[i];
						c.ky -= my[i];
						que.push(c);
						java[c.tx][c.ty][c.kx][c.ky] = 1;
						c.tx -= mx[i];
						c.ty -= my[i];
						c.kx += mx[i];
						c.ky += my[i];
					}
					else if (java[c.tx][c.ty][c.kx - mx[i]][c.ky - my[i]] == 0 && map[c.tx + mx[i]][c.ty + my[i]] == 1 && map[c.kx - mx[i]][c.ky - my[i]] == 0)
					{
						c.kx -= mx[i];
						c.ky -= my[i];
						que.push(c);
						java[c.tx][c.ty][c.kx][c.ky] = 1;
						c.kx += mx[i];
						c.ky += my[i];
					}
					else if (java[c.tx + mx[i]][c.ty + my[i]][c.kx][c.ky] == 0 && map[c.tx + mx[i]][c.ty + my[i]] == 0 && map[c.kx - mx[i]][c.ky - my[i]] == 1)
					{
						c.tx += mx[i];
						c.ty += my[i];
						que.push(c);
						java[c.tx][c.ty][c.kx][c.ky] = 1;
						c.tx -= mx[i];
						c.ty -= my[i];
					}
				}
			}
			if (c.t < 100)
				cout << c.t << endl;
			else
				cout << "NA" << endl;
		}
	return 0;
}

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

using namespace std;
#define MAX 50

typedef pair<int,int> pi;

const int di[] = {-1,0,1,0};
const int dj[] = {0,1,0,-1};


bool isinside(pi pos, int H, int W){
  return 0<=pos.first&&pos.first<H&&0<=pos.second&&pos.second<W;
}
class State{
public:
  pi taka;
  pi kazu;
  int time;
  State( pi taka, pi kazu, int t ):taka(taka),kazu(kazu),time(t){}
};
int bfs(int sti, int stj, int ski, int skj, int H, int W, bool M[][MAX]){
  bool vis[H][W][H][W];
  for(int i = 0; i < H; ++i){
    for(int j = 0; j < W; ++j){
      for(int k = 0; k < H; ++k){
	for(int l = 0; l < W; ++l){
	  vis[i][j][k][l] = false;
	}
      }
    }
  }

  State st(pi(sti,stj),pi(ski,skj),0);
  queue<State> qs;
  qs.push( st );
  while(!qs.empty()){
    State now = qs.front();
    qs.pop();
    //cout << now.taka.first << ' ' << now.taka.second << ' ' << now.kazu.first << ' ' << now.kazu.second << endl;
    if( now.taka.first == now.kazu.first && now.taka.second == now.kazu.second ){
      return now.time;
    }
    for(int k = 0; k < 4; ++k){
      pi ntaka( now.taka.first+di[k], now.taka.second+dj[k] );
      pi nkazu( now.kazu.first+di[(k+2)%4], now.kazu.second+dj[(k+2)%4]);
      if( !isinside(ntaka,H,W ) || M[ntaka.first][ntaka.second] ){
	ntaka = now.taka;
      }
      if( !isinside(nkazu,H,W ) || M[nkazu.first][nkazu.second] ){
	nkazu = now.kazu;
      }
      if( !vis[ntaka.first][ntaka.second][nkazu.first][nkazu.second] ){
	vis[ntaka.first][ntaka.second][nkazu.first][nkazu.second] = true;
      
	State next( ntaka, nkazu, now.time+1 );
	qs.push( next );
      }
    }
  }
  return -1;
}

int main()
{
  while(true){
    int H, W;
    
    cin >> H >> W;
    if( H == 0 && W == 0 ) break;
    bool m[MAX][MAX];
    int tx,ty;
    int kx,ky;  
    cin >> tx >> ty;
    cin >> kx >> ky;
    --tx;--ty;--kx;--ky;
    for(int i = 0; i < H; ++i){
      for(int j = 0; j < W; ++j){
	cin >> m[i][j];
      }
    }
    int ans = bfs( ty, tx, ky, kx, H, W, m);
    if( ans < 0 ){
      cout << "NA" << endl;
    }
    else{
      cout << ans << endl;
    }
  }
  return 0;
}

C++: #include<queue>
#include<cstdio>

#define	mp	make_pair

using namespace std;

typedef	pair<int,int>	pii;

const int dx[]={1,0,-1,0},dy[]={0,-1,0,1};
int w,h;
unsigned char board[50][50],memo[50][50][50][50];

int main(){
	for(;scanf("%d%d",&w,&h),w;){
		int tx,ty,kx,ky;	scanf("%d%d%d%d",&tx,&ty,&kx,&ky);
		for(int i=0;i<h;i++)for(int j=0;j<w;j++)	scanf("%d",board[i]+j);
		for(int i=0;i<h;i++)for(int j=0;j<w;j++)for(int k=0;k<h;k++)for(int l=0;l<w;l++)	memo[i][j][k][l]=255;

		int ans=-1;
		memo[ty][tx][ky][kx]=0;
		queue< pair<pii,pii> > qu;	qu.push(mp(mp(ty,tx),mp(ky,kx)));
		while(!qu.empty()){
			pair<pii,pii> a=qu.front();	qu.pop();
			int tx=a.first.second, ty=a.first.first;
			int kx=a.second.second,ky=a.second.first;
			int cost=memo[ty][tx][ky][kx];
			if(cost>=100)	break;
			if(ty==ky && tx==kx){
				ans=cost;
				break;
			}
			for(int i=0;i<4;i++){
				int txx=tx+dx[i],tyy=ty+dy[i];
				int kxx=kx-dx[i],kyy=ky-dy[i];
				if(!(0<=txx && txx<w && 0<=tyy && tyy<h && !board[tyy][txx]))	txx=tx,tyy=ty;
				if(!(0<=kxx && kxx<w && 0<=kyy && kyy<h && !board[kyy][kxx]))	kxx=kx,kyy=ky;
				if(cost+1<memo[tyy][txx][kyy][kxx]){
					memo[tyy][txx][kyy][kxx]=cost+1;
					qu.push(mp(mp(tyy,txx),mp(kyy,kxx)));
				}
			}
		}

		printf(~ans?"%d\n":"NA\n",ans);
	}

	return 0;
}