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 (pq PQStatus) Len() int {
	return len(pq)
}
func (pq PQStatus) Less(i, j int) bool {
	if pq[i].Turn == pq[j].Turn {
		return pq[i].Person.Distance() < pq[j].Person.Distance()
	}
	return pq[i].Turn < pq[j].Turn
}

func (pq PQStatus) Swap(i, j int) {
	pq[i], pq[j] = pq[j], pq[i]
}

func (pq *PQStatus) Push(x interface{}) {
	item := x.(*Status)
	*pq = append(*pq, item)
}

func (pq *PQStatus) Pop() interface{} {
	old := *pq
	n := len(old)
	item := old[n-1]
	*pq = old[0 : n-1]
	return item
}

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)
	//heap.Init(&pq)
	//heap.Push(&pq, start)
	pq.Push(start)
	dx := []int64{0, 1, 0, -1}
	dy := []int64{1, 0, -1, 0}
	memo := make(map[PersonPosition]int64, 0)
	ans := int64(101)
	for pq.Len() > 0 {
		//now := heap.Pop(&pq).(*Status)
		now := pq.Pop().(*Status)
		if now.Person.Distance() == 0 && ans > now.Turn {
			ans = now.Turn
		}
		if v, ok := memo[now.Person]; ok && v <= now.Turn {
			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 += 1
			if next.Turn < 100 {
				//heap.Push(&pq, next)
				pq.Push(next)
			}
		}
	}
	if ans == 101 {
		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<bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(int)(n);i++)
using namespace std;
typedef pair<int,int> pii;
typedef pair<pii,pii> state;

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

int main(){
  int w,h;
  while(cin >> w >> h, w){
    int ax,ay,bx,by;
    cin >> ax >> ay >> bx >> by;
    state init(pii(ax,ay),pii(bx,by));
    
    vector< vector<int> > g(h+2,vector<int>(w+2,1));
    rep(i,h)rep(j,w){
      cin >> g[i+1][j+1];
    }

    queue<state> q;
    q.push(init);
    map<state, int> d;
    d[init] = 0;

    int ans = 1000;
    while(q.size()){
      state cur = q.front(); q.pop();
      if(ax==bx && ay==by){
	ans = d[cur]; break;
      }

      if(d[cur]==99)continue;
      ax = cur.first.first; ay = cur.first.second;
      bx = cur.second.first; by = cur.second.second;

      rep(a,4){
	int nax = ax+dx[a], nay = ay+dy[a];
	int nbx = bx-dx[a], nby = by-dy[a];

	if(g[nay][nax])nay = ay, nax = ax;
	if(g[nby][nbx])nby = by, nbx = bx;

	state nxt(pii(nax,nay),pii(nbx,nby));
	if(d.count(nxt))continue;

	d[nxt] = d[cur] + 1;
	q.push(nxt);
      }
    }

    if(ans>=100)cout << "NA" << endl;
    else cout << ans << endl;
  }
}

C++: #include<stdio.h>
#include<iostream>
#include<queue>
#include<string.h>
using namespace std;
struct oza{
	int x;
	int y;
};
int A[50][50][50][50];
int main(){
	oza k;
	oza t;
	queue<oza> ka;
	queue<oza> ta;
	queue<int> Z;
	int  w,h,b;
	int d=0,c=0,i=0,j=0,l=-1,D[52][52];
	int tx[4]={ 1, 0,-1,0 };       
	int kx[4]={-1, 0, 1,0 };
	int ty[4]={ 0, 1, 0,-1 };
	int ky[4]={ 0, -1, 0,1};
	scanf("%d %d",&w,&h);
	while(w!=0&&h!=0){
	memset(A,0,sizeof(A));
		for(i=0;i<=h+1;i++){
		for(j=0;j<=w+1;j++){
		D[i][j]=1; //??¨????????????????????\?????? 
		}
	}

	scanf("%d %d",&t.x,&t.y);
	scanf("%d %d",&k.x,&k.y);
	for(i=1;i<=h;i++){
		for(j=1;j<=w;j++){
		scanf("%d",&D[i][j]);
		}
	}
	ta.push(t);
	ka.push(k);
	Z.push(c);
		if(t.x==k.x&&t.y==k.y){
			d=-1;
		}
	while(d!=-1){
		l++;
		if(l==4){
		l=0;
		t=ta.front();
		k=ka.front();
		ka.pop();
		ta.pop();
		Z.pop();
		A[t.x][t.y][k.x][k.y]=1;
		}
		if(c==100||Z.empty()){
			printf("NA");
		break;
		}
	
		// ?????\????????????????????¨?????¨??????
		t=ta.front();
		k=ka.front();
		c=Z.front();
		
		t.x=t.x+tx[l];
		t.y=t.y+ty[l];
		k.x=k.x+kx[l];
		k.y=k.y+ky[l];
		
		if(D[t.x][t.y]==1){
		t.x=t.x-tx[l];
		t.y=t.y-ty[l];
		}
		if(D[k.x][k.y]==1){
		k.x=k.x-kx[l];
		k.y=k.y-ky[l];
		}
		if(A[t.x][t.y][k.x][k.y]==1){
			continue;
		}
		
		ta.push(t);
		ka.push(k);
		c=c+1;
		Z.push(c);
		
		if(t.x==k.x&&t.y==k.y){
			printf("%d\n",Z.back());
			break;
		}	
		
		
	}
	while(!ka.empty()){
	ka.pop();
	ta.pop();
	Z.pop();
	}
	c=0;
	l=-1;
	scanf("%d %d",&w,&h);
	}	
	return 0;

}

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

using namespace std ;

struct ST
{
	int tx ,ty ;
	int kx ,ky ;
	int cnt ;
	ST( int a ,int s ,int d ,int f ,int g ) : tx( a ) ,ty( s ) ,kx( d ) ,ky( f ) ,cnt( g ){}
} ;

int mx[ 4 ] = { 1 ,0 ,0 ,-1 } ;
int my[ 4 ] = { 0 ,1 ,-1 ,0 } ;
int map[ 50 ][ 50 ] ;

int w ,h ;
int tx ,kx ;
int ty ,ky ;

void ans()
{
	queue< ST > que ;
	bool came[ 50 ][ 50 ][ 50 ][ 50 ] = { false } ;
	que.push( ST( tx - 1 ,ty - 1 ,kx - 1 ,ky - 1 ,0 ) ) ;
	came[ tx - 1 ][ ty - 1 ][ kx - 1 ][ ky - 1 ] = true ;
	while( ! que.empty() )
	{
		ST st = que.front() ;
		if( st.tx == st.kx && st.ty == st.ky )
		{
			cout << st.cnt << endl ;
			return ;
		}
		else if( st.cnt >= 100 )
		{
			break ;
		}
		que.pop() ;
		for( int i = 0 ; i < 4 ; i++ )
		{
			int j = 3 - i ;
			tx = st.tx + mx[ i ] ;
			kx = st.kx + mx[ j ] ;
			ty = st.ty + my[ i ] ;
			ky = st.ky + my[ j ] ;
			if( tx < 0 || tx >= w || ty < 0 || ty >= h || map[ ty ][ tx ] == 1 )
			{
				tx = st.tx ;
				ty = st.ty ;
			}
			if( kx < 0 || kx >= w || ky < 0 || ky >= h || map[ ky ][ kx ] == 1 )
			{
				kx = st.kx ;
				ky = st.ky ;
			}
			if( came[ tx ][ ty ][ kx ][ ky ] == false )
			{
				que.push( ST( tx ,ty ,kx ,ky ,st.cnt + 1 ) ) ;
				came[ tx ][ ty ][ kx ][ ky ] = true ;
			}
		}
	}
	cout << "NA" << endl ;
}

int main()
{
	while( cin >> w >> h ,h )
	{
		cin >> tx >> ty ;
		cin >> kx >> ky ;
		for( int i = 0 ; i < h ; i++ )
		{
			for( int j = 0 ; j < w ; j++ )
			{
				cin >> map[ i ][ j ] ;
			}
		}
		ans() ;
	}
}