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

		if now.Person.Distance() == 0 && ans > now.Turn {
			ans = 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 <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <queue>
#include <cstring>

#define REP(i,k,n) for(int i=k;i<n;i++)
#define rep(i,n) for(int i=0;i<n;i++)
#define INF 1<<30

using namespace std;

int dx[4] = {1,0,-1,0};
int dy[4] = {0,1,0,-1};

struct Data
{
	int tx,ty,kx,ky,cost;

	Data(int tx,int ty,int kx,int ky,int cost) : tx(tx),ty(ty),kx(kx),ky(ky),cost(cost) {}
};

int main()
{
	int x,y;
	while(cin >> x >> y)
	{
		if(x == 0 && y == 0) break;

		int tx,ty,kx,ky;
		cin >> tx >> ty >> kx >> ky;

		tx--;
		ty--;
		kx--;
		ky--;

		int field[55][55];
		memset(field,0,sizeof(field));

		rep(i,y) rep(j,x) cin >> field[i][j];

	   	bool used[52][52][52][52];
		rep(i,52) rep(j,52) rep(k,52) rep(l,52) used[i][j][k][l] = false;
		used[tx][ty][kx][ky] = true;

		queue<Data> que;
		que.push(Data(tx,ty,kx,ky,0));
		
		bool flag = false;
		int ans;

		while(que.size())
		{
			Data data = que.front();
			que.pop();

			if(data.cost >= 100) break;

			if(data.tx == data.kx && data.ty == data.ky)
			{
				flag = true;
				ans = data.cost;
				break;
			}

			rep(i,4)
			{
				int ntx = data.tx + dx[i];
				int nty = data.ty + dy[i];
				int nkx = data.kx + dx[(i+2)%4];
				int nky = data.ky + dy[(i+2)%4];

				Data nd(data.tx,data.ty,data.kx,data.ky,data.cost+1);

				if(0 <= ntx && ntx < x && 0 <= nty && nty < y && field[ntx][nty] == 0)
				{
					nd.tx = ntx;
					nd.ty = nty;
				}

				if(0 <= nkx && nkx < x && 0 <= nky && nky < y && field[nkx][nty] == 0)
				{
					nd.kx = nkx;
					nd.ky = nky;
				}

				if(!used[nd.tx][nd.ty][nd.kx][nd.ky])
				{
					used[nd.tx][nd.ty][nd.kx][nd.ky] = true;
					que.push(nd);
				}
			}

		}

		if(flag) cout << ans << endl;
		else cout << "NA" << endl;
	}
}

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

using namespace std;
#define MAX 64

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]){
  static bool vis[50][50][50][50];
  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 );
  vis[sti][stj][ski][skj]=true;
  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 ) ){
	ntaka = now.taka;
      }else{
	if( M[ntaka.first][ntaka.second] )
	  ntaka = now.taka;
      }

      if( !isinside(nkazu,H,W ) ){
	nkazu = now.kazu;
      }else{
	if( 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;
}