Go: package main

import (
	"container/heap"
	"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)
	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)
	dx := []int64{0, 1, 0, -1}
	dy := []int64{1, 0, -1, 0}
	memo := make(map[PersonPosition]struct{}, 0)
	for pq.Len() > 0 {
		now := heap.Pop(&pq).(*Status)
		if now.Person.Distance() == 0 {
			fmt.Println(now.Turn)
			return
		}
		if _, ok := memo[now.Person]; ok {
			continue
		}
		memo[now.Person] = struct{}{}
		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)
			}
		}
	}
	fmt.Println("NA")
}

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 H,W;
class Point{
public:
  int tx; //タカユキの座標
  int ty;
  int kx; //カズユキの座標
  int ky;
  int d; //ターン回数
  void set(int a,int b,int c,int d){
    tx = a;
    ty = b;
    kx = c;
    ky = d;
  }
};
int is_out_of_area(int y,int x) //座標が範囲内か確認する関数
{
  return x < 1 || x > W || y < 1 || y > H;
}
int main(){

  while(1){
    bool F[52][52]; //障害物
    bool D[52][52][52][52]; //探索済みかの判定用
    Point p;
    int tx,ty,kx,ky;
    queue<Point> qa;
    cin >> W >> H;
    if(W == 0 && H == 0)
    break;
    cin >> tx >> ty >> kx >> ky;
    for(int y=0;y<=H+1;y++){
      for(int x=0;x<=W+1;x++){
        F[y][x] = 1;
      }
    }
    for(int y=1;y<=H;y++){
      for(int x=1;x<=W;x++){
        int a;
        cin >> a;
        F[y][x] = a;
        for(int i=1;i<=H;i++){
          for(int j=1;j<=W;j++){
            D[y][x][i][j] = 1; //1:未探索 , 0:探索済み
          }
        }
      }
    }
    p.set(tx,ty,kx,ky);
    p.d = 0;
    qa.push(p);
    while(1){
      int inc_tx,inc_ty,inc_kx,inc_ky;
      if(qa.empty()){
        cout << "NA" <<endl;
        break;
      }
      p = qa.front();
      qa.pop();
      if(p.d >= 100){
        cout << "NA" << endl;
        break;
      }
      if(p.tx == p.kx && p.ty == p.ky){
        cout << p.d << endl;
        break;
      }
      if(D[p.ty-1][p.tx][p.ky+1][p.kx]){ //タカユキの y 座標を-1, カズユキを+1 同様の if 文が下に四つ続く
        int inc_ty = -1 , inc_ky = 1;
        if(is_out_of_area(p.ty-1,p.tx) || F[p.ty-1][p.tx]){ //範囲外または障害物にあたったならば移動しない
          inc_ty = 0;
        }
        if(is_out_of_area(p.ky+1,p.kx) || F[p.ky+1][p.kx]){ //範囲外または障害物にあたったならば移動しない
          inc_ky = 0;
        }
      }
      if(inc_ty || inc_ky){ //どちらかが動ける状態であったならキューにプッシュ
        Point q;
        q.set(p.tx,p.ty + inc_ty,p.kx,p.ky+inc_ky);
        q.d = p.d + 1;
        qa.push(q);
        D[p.ty + inc_ty][p.tx][p.ky + inc_ky][p.kx] = 0;
      }
      if(D[p.ty+1][p.tx][p.ky-1][p.kx]){
        int inc_ty = 1 , inc_ky = -1;
        if(is_out_of_area(p.ty+1,p.tx) || F[p.ty+1][p.tx]){inc_ty = 0;
        }
        if(is_out_of_area(p.ky-1,p.kx) || F[p.ky-1][p.kx]){
          inc_ky = 0;
        }
      }
      if(inc_ty || inc_ky){
        Point q;
        q.set(p.tx,p.ty + inc_ty,p.kx,p.ky+inc_ky);
        q.d = p.d + 1;
        qa.push(q);
        D[p.ty + inc_ty][p.tx][p.ky + inc_ky][p.kx] = 0;
      }
      if(D[p.ty][p.tx-1][p.ky][p.kx+1]){
        int inc_tx = -1 , inc_kx = 1;
        if(is_out_of_area(p.ty,p.tx + inc_tx) || F[p.ty][p.tx + inc_tx]){
          inc_tx = 0;
        }
        if(is_out_of_area(p.ky,p.kx + inc_kx) || F[p.ky][p.kx + inc_kx]){
          inc_kx = 0;
        }
        if(inc_tx || inc_kx){
          Point q;
          q.set(p.tx + inc_tx,p.ty,p.kx + inc_kx,p.ky);
          q.d = p.d + 1;
          qa.push(q);
          D[p.ty][p.tx + inc_tx][p.ky][p.kx + inc_kx] = 0;
        }
      }
      if(D[p.ty][p.tx+1][p.ky][p.kx-1]){
        int inc_tx = 1 , inc_kx = -1;
        if(is_out_of_area(p.ty,p.tx + inc_tx) || F[p.ty][p.tx + inc_tx]){
          inc_tx = 0;
        }
        if(is_out_of_area(p.ky,p.kx + inc_kx) || F[p.ky][p.kx + inc_kx]){
          inc_kx = 0;
        }
      }
      if(inc_tx || inc_kx){
        Point q;
        q.set(p.tx + inc_tx,p.ty,p.kx + inc_kx,p.ky);
        q.d = p.d + 1;
        qa.push(q);
        D[p.ty][p.tx + inc_tx][p.ky][p.kx + inc_kx] = 0;
      }
    }
    while(!qa.empty()){
      qa.pop();
    } //キューの残りカスを消去
  }
  return 0;
}

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;
    }
  }
}