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<cstring>
#include<iostream>
#include<vector>
#include<algorithm>
#include<queue>
#include<stack>
using namespace std;
struct P{
  P(){};
  P(int a,int b){
    x=a,y=b;
  }
  int x,y;
  void move(int,int);
};
struct S{
  S(){};
  S(P a,P b){
    t=a;
    k=b;
  }
  P t,k;
  void move(int);
};
 
P size;
S f_pos;
vector<vector<int> > f;
bool input(){
  size=P();
  f_pos=S();
  f.clear();
  cin>>size.y>>size.x;
  if(size.x==0&&size.y==0)return false;
  cin>>f_pos.t.y>>f_pos.t.x;
  cin>>f_pos.k.y>>f_pos.k.x;
  vector<int> t;
  for(int i=0;i<size.y+2;i++){
    t.push_back(1);
  }
  f.push_back(t);
  for(int i=0;i<size.x;i++){
    vector<int> tt;
    tt.push_back(1);
    for(int j=0;j<size.y;j++){
      int tmp;
      cin>>tmp;
      tt.push_back(tmp);
    }
    tt.push_back(1);
    f.push_back(tt);
  }
  f.push_back(t);
  return true;
}
int cost[60][60][60][60];
const int vx[]={0,0,1,-1};
const int vy[]={1,-1,0,0};
void S::move(int i){
  t.move(vx[i],vy[i]);
  k.move(-vx[i],-vy[i]);
}
void P::move(int a,int b){
  if(f[x+a][y+b]!=1){
    x+=a;
    y+=b;
  }
}
int solve(){
  memset(cost,-1,(60*60*60*60)*sizeof(cost));
  queue<S> q;
  q.push(f_pos);
  cost[f_pos.t.x][f_pos.t.y][f_pos.k.x][f_pos.k.y]=0;
  while(!q.empty()){
    S now = q.front();q.pop();
    for(int i=0;i<4;i++){
      S tmp = now;
      tmp.move(i);
      if(cost[tmp.t.x][tmp.t.y][tmp.k.x][tmp.k.y]!=-1)continue;
 
      cost[tmp.t.x][tmp.t.y][tmp.k.x][tmp.k.y] = cost[now.t.x][now.t.y][now.k.x][now.k.y]+1;
      if(cost[tmp.t.x][tmp.t.y][tmp.k.x][tmp.k.y]>=100){
        return -1;
      }else if( (tmp.t.x==tmp.k.x)&&(tmp.t.y==tmp.k.y) ){
        return cost[tmp.t.x][tmp.t.y][tmp.k.x][tmp.k.y];
      }else{
        q.push(tmp);
      }
    }
  }
  return -1;
}
int main(){
  while(input()){
    /*
    for(int i=0;i<f.size();i++){
      for(int j=0;j<f[i].size();j++){
        cout<<f[i][j];
      }cout<<endl;
    }cout<<endl;
    */
    int ans= solve();
    if(ans==-1||ans>=100){
      cout<<"NA"<<endl;
    }else{
      cout<<ans<<endl;
    }
  }
}

C++: 

#include<stdio.h>
#include<iostream>
#include<queue>
#include<string.h>
#include<cstring>
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.tx][S.ty]==1){
		S.tx=S.tx-tx[l];
		S.ty=S.ty-ty[l];
		}
		if(D[S.kx][S.ky]==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;

}

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

#define MAX_X 50
#define MAX_Y 50

using namespace std;

typedef pair<int,int> P;
typedef pair<P,P> PP;

short d[MAX_Y][MAX_X][MAX_Y][MAX_X];

int tx,ty,kx,ky,ntx,nty,nkx,nky;
int ans;

short maze[MAX_Y][MAX_X];
int Y,X;

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

bool bfs(){
	queue<PP> que;
	map<PP,int> mat;
	que.push(make_pair(make_pair(ty,tx),make_pair(ky,kx)));
	
	mat[que.front()]=0;
	while (que.size()) {
		PP p=que.front();
		que.pop();
		if (d[p.first.first][p.first.second][p.second.first][p.second.second]>=100) {
			return false;
		}
		if (p.first.first==p.second.first&&p.first.second==p.second.second) {
			ans=d[p.first.first][p.first.second][p.second.first][p.second.second];
			return true;
		}
		
		if (mat[que.front()]) {
			continue;
		}
		for (int i=0; i<4; i++) {
			ntx=p.first.second+dx[i],nty=p.first.first+dy[i],nkx=p.second.second+dx[i]*(-1),nky=p.second.first+dy[i]*(-1);
			int flag=2;
			if (!(0<=ntx&&ntx<X&&0<=nty&&nty<Y&&maze[nty][ntx]!=1)){
				flag-=1;
				ntx=p.first.second;
				nty=p.first.first;
			}
			if (!(0<=nkx&&nkx<X&&0<=nky&&nky<Y&&maze[nky][nkx]!=1)) {
				flag-=1;
				nkx=p.second.second;
				nky=p.second.first;
			}
			if (flag!=0) {
				que.push(make_pair(make_pair(nty,ntx),make_pair(nky,nkx)));
				d[nty][ntx][nky][nkx]=d[p.first.first][p.first.second][p.second.first][p.second.second]+1;
				mat[que.front()] = d[nty][ntx][nky][nkx];
			}
			
		}
	}
	return false;
}

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