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<cstring>
#include<cstdlib>
#include<iostream>
#include<vector>
#include<algorithm>
#include<queue>
#include<stack>
using namespace std;


struct S{
  S(){};
  int tx,ty,kx,ky;
};
int X,Y;
S s;
vector<vector<int> > f;

bool input(){
  f.clear();
  s=S();
  cin>>X>>Y;
  if(X==0&&Y==0)return false;
  cin>>s.tx>>s.ty;
  cin>>s.kx>>s.ky;
  swap(s.tx,s.ty);
  swap(s.kx,s.ky);
  vector<int> kabe;
  for(int i=0;i<X+2;i++){
    kabe.push_back(1);
  }
  f.push_back(kabe);
  for(int i=0;i<Y;i++){
    vector<int> tt;
    tt.push_back(1);
    for(int j=0;j<X;j++){
      int tmp;
      cin>>tmp;
      tt.push_back(tmp);
    }
    tt.push_back(1);
    f.push_back(tt);
  }
  f.push_back(kabe);
  return true;
}

int vx[]={0,0,1,-1};
int vy[]={1,-1,0,0};
int used[50][50][50][50];
queue<S> q;
int bfs(S pos){
  memset(used,-1,(50*50*50*50));
  q = queue<S>();
  q.push(pos);
  used[pos.tx][pos.ty][pos.kx][pos.ky]=0;
  while(!q.empty()){
    S now = q.front();q.pop();
    if(used[now.tx][now.ty][now.kx][now.ky]>=100){
      return -1;
    }
    if(now.tx==now.kx&&now.ty==now.ky){
      return used[now.tx][now.ty][now.kx][now.ky];
    }
    for(int i=0;i<4;i++){
      S tmp = now;
      bool a,b;
      if(a=(f[tmp.tx+vx[i]][tmp.ty+vy[i]]!=1)){
        tmp.tx += vx[i];
        tmp.ty += vy[i];
      }
      if(b=(f[tmp.kx-vx[i]][tmp.ky-vy[i]]!=1)){
        tmp.kx -= vx[i];
        tmp.ky -= vy[i];
      }
      if((!(a||b))||(used[tmp.tx][tmp.ty][tmp.kx][tmp.ky]!=-1)){
        continue;
      }
      used[tmp.tx][tmp.ty][tmp.kx][tmp.ky]=used[now.tx][now.ty][now.kx][now.ky]+1;
      q.push(tmp);
    }
  }
  return -1;
}

int solve(){
  return bfs(s);
}

int main(){
  while(input()){
    int ans = solve();
    if(ans>=0){
      cout<<ans<<endl;
    }else{
      cout<<"NA"<<endl;
    }
  }
}

C++: #include<iostream>
#include<queue>
#include<algorithm>
#include<map>
using namespace std;

int w,h;
int tx,ty,kx,ky;
class point{
	public:
	int x;
	int y;
};


class State{//?????????????????????????????????????????¨????????????
	public:
	int x1;
	int y1;
	int x2;
	int y2;
	int ans;
	State(int a,int b,int c,int d,int aa){
		x1=a;
		y1=b;
		x2=c;
		y2=d;
		ans=aa;
	}

};


map< pair<pair<int,int>,pair<int,int> >,bool>visited;



const int WIDTH=55;
const int HEIGHT=55;
const int OUT=-3;
int table[WIDTH][HEIGHT];

int main(){

	while(true){
		cin>>w>>h;
		if(w==0&&h==0)break;
		cin>>tx>>ty;
		cin>>kx>>ky;
		for(int i=0;i<=WIDTH;i++){
			for(int j=0;j<=HEIGHT;j++)table[i][j]=OUT;//??????
		}
		for(int i=1;i<=h;i++){
			for(int j=1;j<=w;j++){
				cin>>table[i][j];
			}
		}
	
		State first(tx,ty,kx,ky,0);//???????????¶???
		queue<State>bfs;
		bfs.push(first);
	
		visited[make_pair(make_pair(tx,ty),make_pair(tx,ty))]=true;
	
	
	
		int moveX1[]={1,0,-1,0},moveY1[]={0,1,0,-1};//?????????????????????
	
		int moveX2[]={-1,0,1,0},moveY2[]={0,-1,0,1};//?????????????????????
	
		bool ok=false;
		while(!bfs.empty()){
			int x1,y1,x2,y2,ans;
			State now=bfs.front();
			bfs.pop();
			x1=now.x1;
			y1=now.y1;
			x2=now.x2;
			y2=now.y2;
			ans=now.ans;
		
		
			//\\cout<<x1<<" "<<y1<<" "<<x2<<" "<<y2<<" "<<ans<<endl;
			if(x1==x2&&y1==y2){
				cout<<ans<<endl;//??????????????????????????????
				ok=true;
					break;
				}	
			if(ans>100){
				cout<<"NA"<<endl;
				ok=true;
				break;
			}

			//??\???????¬??????????
			int nextX1,nextY1,nextX2,nextY2;//??????????¬??????§?¨?
			int place1,place2;//??????????¬??????´???(????????????????????????)
			//4??????????????????
			for(int i=0;i<4;i++){
		
				nextX1=x1+moveX1[i];
				nextY1=y1+moveY1[i];
				nextX2=x2+moveX2[i];
				nextY2=y2+moveY2[i];
			
				place1=table[nextX1][nextY1];
				place2=table[nextX2][nextY2];
			
				if(place1==OUT||place1==1){//????????????????????????????????????????????????
					nextX1=x1;//????????????
					nextY1=y1;//????????????
				}
			
				if(place2==OUT||place2==1){
					nextX2=x2;//????????????
					nextY2=y2;//????????????
				}
			
				if(visited[make_pair(make_pair(nextX1,nextY1),make_pair(nextX2,nextY2))]==false){
					State next(nextX1,nextY1,nextX2,nextY2,ans+1);
					bfs.push(next);//ans???1????????????????????\????????\??????
					visited[make_pair(make_pair(nextX1,nextY1),make_pair(nextX2,nextY2))]=true;//?¨??????????
					//cout<<nextX1<<" "<<nextY1<<" "<<nextX2<<" "<<nextY2<<" "<<endl;
				}
			}
		
		}
	
		if(!ok)cout<<"NA"<<endl;
	}
	return 0;
}


/*



0 0 0 0 1 0
0 1 0 0 0 0
0 1 0 0 0 0
0 0 0 1 0 0
0 0 0 0 0 1
0 0 0 0 0 0


*/