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 <queue>
#include <cstring>
using namespace std;

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

bool f[50][50];
bool h[50][50][50][50];

class State
{
public:
	int lx,ly,rx,ry,c;
	State(int lx, int ly, int rx, int ry, int c)
	:lx(lx),ly(ly),rx(rx),ry(ry),c(c)
	{}
};
int main()
{
	int W,H;
	while(cin >> W >> H, (W||H))
	{
		memset(h,0,sizeof(h));

		int lx,ly,rx,ry;
		cin >> lx >> ly >> rx >> ry;

		lx--; ly--;
		rx--; ry--;

		for(int i=0; i<H; i++)
		for(int j=0; j<W; j++)
			cin >> f[j][i];

		queue<State> q;
		q.push(State(lx,ly,rx,ry,0));

		bool g=false;
		while(!q.empty())
		{
			State s = q.front(); q.pop();
			if(s.c >= 100) break;

			if(s.lx==s.rx&&s.ly==s.ry)
			{
				g=true;
				cout << s.c << endl;
				break;
			}

			for(int i=0; i<4; i++)
			{
				int tlx=s.lx+dx[i], tly=s.ly+dy[i];
				int trx=s.rx+dx[(i+2)%4], ttry=s.ry+dy[(i+2)%4];

				if(tlx<0||tlx>=W||tly<0||tly>=H) continue;
				if(trx<0||trx>=W||ttry<0||ttry>=H) continue;

				if(f[tlx][tly])
				{
					tlx = s.lx;
					tly = s.ly;
				}
				if(f[trx][ttry])
				{
					trx = s.rx;
					ttry = s.ry;
				}

				if(h[tlx][tly][trx][ttry]) continue;
				h[tlx][tly][trx][ttry]=1;
				
				q.push(State(tlx,tly,trx,ttry,s.c+1));

			}
		}

		if(!g) cout << "NA" << endl;

	}
}

C++: #include<iostream>
#include<queue>
#include<map>
using namespace std;
const int INF=(1<<21);
typedef pair<int,int> P;
int x,y;
int tx,ty;
int kx,ky;
int t_check[50][50];
int k_check[50][50];
int depart[50][50];
int dx[]={1,0,-1,0},dy[]={0,-1,0,1};
int ans=0;

int bfs(){
  queue<P> t_que;
  queue<P> k_que;

  for(int i=0;i<y;i++){
    for(int j=0;j<x;j++){
      t_check[i][j]=k_check[i][j]=INF;
    }
  }

  t_check[ty][tx]=0;
  k_check[ky][kx]=0;

  t_que.push(P(ty,tx));
  k_que.push(P(ky,kx));

  while(t_que.size()){
    P tp=t_que.front();t_que.pop();
    P kp=k_que.front();k_que.pop();
    if(tp.first==kp.first && tp.second==kp.second){
      return t_check[tp.first][tp.second];
    }

    for(int i=0;i<4;i++){
      int tnx=tp.second+dx[i];
      int tny=tp.first+dy[i];
      int knx=kp.second-(dx[i]);
      int kny=kp.first-(dy[i]);

      if(0<=tnx && tnx<x && 0<=tny && tny<y && depart[tny][tnx]!=1 && t_check[tny][tnx]==INF  &&  0<=knx && knx<x && 0<=kny && kny<y && depart[kny][knx]!=1 && k_check[kny][knx]==INF){

	t_que.push(P(tny,tnx));
	k_que.push(P(kny,knx));
	t_check[tny][tnx]=t_check[tp.first][tp.second]+1;
	k_check[kny][knx]=k_check[kp.first][kp.second]+1;

      }
    }
  }
  return -1;
}
int main(){
  while(1){
    cin>> x>> y;
  if(x==0 && y==0){
    break;
  }
  cin>> tx>> ty;
  cin>> kx>> ky;
  for(int i=0;i<y;i++){
    for(int j=0;j<x;j++){
      cin>> depart[i][j];
    }
  }
  ans=bfs();
  if(ans==-1){
    cout<< "NA"<<endl;
  }else{
    cout<< ans<< endl;
  }
  }
}

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)
			{
				rep1(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 (!que.empty())
			{
				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)
				{
					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]] != 0 && 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]] != 0)
					{
						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.tx == c.kx&&c.ty == c.ky)
				cout << c.t << endl;
			else
				cout << "NA" << endl;
		}
	return 0;
}