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
		}
		if ans<=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 <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(){
  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;
  while(1){

    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){
      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<queue>
#include<cstdio>

#define	mp	make_pair

using namespace std;

typedef	pair<int,int>	pii;

const int dx[]={1,0,-1,0},dy[]={0,-1,0,1};
int w,h;
unsigned char board[50][50],memo[50][50][50][50];

int main(){
	for(;scanf("%d%d",&w,&h),w;){
		int tx,ty,kx,ky;	scanf("%d%d%d%d",&tx,&ty,&kx,&ky);
		tx--,ty--,kx--,ky--;
		for(int i=0;i<h;i++)for(int j=0;j<w;j++)	scanf("%d",board[i]+j);
		for(int i=0;i<h;i++)for(int j=0;j<w;j++)for(int k=0;k<h;k++)for(int l=0;l<w;l++)	memo[i][j][k][l]=255;

		int ans=-1;
		memo[ty][tx][ky][kx]=0;
		queue< pair<pii,pii> > qu;	qu.push(mp(mp(ty,tx),mp(ky,kx)));
		while(!qu.empty()){
			pair<pii,pii> a=qu.front();	qu.pop();
			int tx=a.first.second, ty=a.first.first;
			int kx=a.second.second,ky=a.second.first;
			int cost=memo[ty][tx][ky][kx];
			if(cost>=100)	break;
			if(ty==ky && tx==kx){
				ans=cost;
				break;
			}
			for(int i=0;i<4;i++){
				int txx=tx+dx[i],tyy=ty+dy[i];
				int kxx=kx-dx[i],kyy=ky-dy[i];
				if(!(0<=txx && txx<w && 0<=tyy && tyy<h && !board[tyy][txx]))	txx=tx,tyy=ty;
				if(!(0<=kxx && kxx<w && 0<=kyy && kyy<h && !board[kyy][kxx]))	kxx=kx,kyy=ky;
				if(cost+1<memo[tyy][txx][kyy][kxx]){
					memo[tyy][txx][kyy][kxx]=cost+1;
					qu.push(mp(mp(tyy,txx),mp(kyy,kxx)));
				}
			}
		}

		printf(~ans?"%d\n":"NA\n",ans);
	}

	return 0;
}