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>
using namespace std;
int dy[]={-1,0,1,0};
int dx[]={0,1,0,-1};
struct state{ int ay,ax,by,bx,cnt; };
int H,W;
int t[50][50];
int visited[50][50][50][50];
bool inField(int y,int x){
  if(y<0||y>=H)return false;
  if(x<0||x>=W)return false;
  if(t[y][x]==1)return false;
  return true;
}
void solve(state s){
  queue < state > Q;
  Q.push(s);
  visited[s.ay][s.ax][s.by][s.bx]=true;
  while(!Q.empty()){
    state now = Q.front(); Q.pop();
    int ay=now.ay,ax=now.ax,by=now.by,bx=now.bx;
    if(now.cnt>100)continue;
    if(ay==by&&ax==bx){ cout<<now.cnt<<endl; return; }
    for(int i=0;i<4;i++){
      int nay=ay+dy[i],nax=ax+dx[i];
      int nby=by-dy[i],nbx=bx-dx[i];
      if(!inField(nay,nax))nay=ay,nax=ax;
      if(!inField(nby,nbx))nby=by,nbx=bx;
      if(visited[nay][nax][nby][nbx])continue;
      visited[nay][nax][nby][nbx]=true;
      Q.push( (state){nay,nax,nby,nbx,now.cnt+1} );
    }
  }
  cout<<"NA"<<endl;
}

int main(){
  while(1){
    cin>>W>>H;
    if(W==0&&H==0)break;
    state s;
    cin>>s.ax>>s.ay>>s.bx>>s.by;
    s.ay--,s.ax--,s.by--,s.bx--;
    s.cnt=0;
    for(int i=0;i<H;i++){
      for(int j=0;j<W;j++){
	cin>>t[i][j];
	for(int k=0;k<H;k++){
	  for(int l=0;l<W;l++){
	    visited[i][j][k][l]=false;
	  }
	}
      }
    }
    solve(s);
  }
}

C++: #include <bits/stdc++.h>

using namespace std;

#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
#define fi first
#define se second

template<typename A, typename B> inline bool chmax(A &a, B b) { if (a<b) { a=b; return 1; } return 0; }
template<typename A, typename B> inline bool chmin(A &a, B b) { if (a>b) { a=b; return 1; } return 0; }

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<int, pii> pip;
typedef pair<pii, pii> ppp;
typedef pair<int, ppp> P;
const ll INF = 1ll<<29;
const ll MOD = 1000000007;
const double EPS  = 1e-9;

int W, H;
pii tp, kp;
int maps[50][50];
bool done[50][50][50][50];

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

bool ok(pii p) {
	if (!(p.fi >= 0 && p.fi < H && p.se >= 0 && p.se < W)) return false;
	if (maps[p.fi][p.se] == 1) return false;
	return true;
}

int main() {
	while (cin >> W >> H, W || H) {
		cin >> tp.se >> tp.fi >> kp.se >> kp.fi;
		tp.se--; tp.fi--; kp.se--; kp.fi--;
		REP(i, H) REP(j, W) scanf("%d", &maps[i][j]);
		
		memset(done, 0, sizeof(done));
		queue<P> que;
		que.push(P(0, ppp(tp, kp)));
		done[tp.fi][tp.se][kp.fi][kp.se] = true;
		
		int ans = INF;
		
		while (!que.empty()) {
			int c = que.front().fi;
			pii p1 = que.front().se.fi, p2 = que.front().se.se;
			que.pop();
			
			if (p1 == p2) { ans = c; break; }
			if (c >= 100) break;
			
			REP(i, 4) {
				pii np1(p1.fi + dy[i], p1.se + dx[i]);
				pii np2(p2.fi + dy[(i+2)%4], p2.se + dx[(i+2)%4]);
				
				bool o1 = ok(np1), o2 = ok(np2);
				if (!o1 && !o2) continue;
				
				np1 = o1 ? np1 : p1;
				np2 = o2 ? np2 : p2;
				if (!chmax(done[np1.fi][np1.se][np2.fi][np2.se], 1)) continue;
				que.push(P(c + 1, ppp(np1, np2)));
			}
		}
		
		if (ans == INF) puts("NA");
		else cout << ans << endl;
		
	}
	return 0;
}

C++: #include<stdio.h>
#include<iostream>
#include<queue>
#include<string.h>
using namespace std;
struct PP{
	int kx;
	int ky;
	int tx;
	int ty;
	int Z;
};
int A[52][52][52][52];
int main(){
	PP S;
	queue<PP> P;
	int  w,h;
	int d=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",&S.tx,&S.ty);
	scanf("%d %d",&S.kx,&S.ky);
	for(i=1;i<=h;i++){
		for(j=1;j<=w;j++){
		scanf("%d",&D[i][j]);
		}
	}
	S.Z=0;
	P.push(S);
		if(S.tx==S.kx&&S.ty==S.ky){
			d=-1;
			printf("%d\n",S.Z);
		}
	while(d!=-1){
		l++;
		if(l==4){
		l=0;
		S=P.front();
		P.pop();
		if(P.empty()){
			printf("NA\n");
		break;
		}
		}
		S=P.front();
		
		S.tx=S.tx+tx[l];
		S.ty=S.ty+ty[l];
		S.kx=S.kx+kx[l];
		S.ky=S.ky+ky[l];
		if(A[S.tx][S.ty][S.kx][S.ky]==1){
			continue;
		}
		A[S.tx][S.ty][S.kx][S.ky]=1;

		if(D[S.ty][S.tx]==1){
		S.tx=S.tx-tx[l];
		S.ty=S.ty-ty[l];
		}
		if(D[S.ky][S.kx]==1){
		S.kx=S.kx-kx[l];
		S.ky=S.ky-ky[l];
		}
		S.Z++;
		P.push(S);
		if(S.tx==S.kx&&S.ty==S.ky){
			printf("%d\n",S.Z);
			break;
		}	
		if(S.Z==100){
			printf("NA\n");
		break;
		}
	}
	while(!P.empty()){
	P.pop();
	}
	l=-1;
	scanf("%d %d",&w,&h);
	}	
	return 0;
}