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)
	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 pq.Len() > 0 {
		//now := heap.Pop(&pq).(*Status)
		//now := pq.Pop().(*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 {
				//heap.Push(&pq, next)
				//pq.Push(next)
				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 H,W;
bool F[52][52]; //障害物
bool D[52][52][52][52]; //探索済みかの判定用

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 || F[y][x];
}

int main(){

  while(1){

    Point p,q;
    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);
    D[ty][tx][ky][kx] = 0;
    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

        inc_ty = -1 ; inc_ky = 1;
        if(is_out_of_area(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)){ //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
          q.set(p.tx,p.ty + inc_ty,p.kx,p.ky+inc_ky);
          q.d = p.d + 1;
          qa.push(q);
          D[q.ty][q.tx][q.ky][q.kx] = 0;
        }

      }

      if(D[p.ty+1][p.tx][p.ky-1][p.kx]){
        inc_ty = 1 ; inc_ky = -1;
        if(is_out_of_area(p.ty+1,p.tx)){
          inc_ty = 0;
        }
        if(is_out_of_area(p.ky-1,p.kx)){
          inc_ky = 0;
        }
        if(inc_ty || inc_ky){
          q.set(p.tx,p.ty + inc_ty,p.kx,p.ky+inc_ky);
          q.d = p.d + 1;
          qa.push(q);
          D[q.ty][q.tx][q.ky][q.kx] = 0;
        }
      }

      if(D[p.ty][p.tx-1][p.ky][p.kx+1]){
        inc_tx = 1 ; inc_kx = 1;
        if(is_out_of_area(p.ty,p.tx + inc_tx)){
          inc_tx = 0;
        }
        if(is_out_of_area(p.ky,p.kx + inc_kx)){
          inc_kx = 0;
        }
        if(inc_tx || inc_kx){
          q.set(p.tx + inc_tx,p.ty,p.kx + inc_kx,p.ky);
          q.d = p.d + 1;
          qa.push(q);
          D[q.ty][q.tx][q.ky][q.kx] = 0;
        }
      }
      if(D[p.ty][p.tx+1][p.ky][p.kx-1]){
        inc_tx = 1 ; inc_kx = -1;
        if(is_out_of_area(p.ty,p.tx + inc_tx)){
          inc_tx = 0;
        }
        if(is_out_of_area(p.ky,p.kx + inc_kx)){
          inc_kx = 0;
        }
        if(inc_tx || inc_kx){
          q.set(p.tx + inc_tx,p.ty,p.kx + inc_kx,p.ky);
          q.d = p.d + 1;
          qa.push(q);
          D[q.ty][q.tx][q.ky][q.kx] = 0;
        }
      }

    }
    while(!qa.empty()){
      qa.pop();
    } //キューの残りカスを消去
  }
  return 0;
}

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

int w,h;
int tx,ty;
int kx,ky;
int maze[100][100]; //y,x
bool d[55][55][55][55]; //tx,ty,kx,ky
int dx[] = {1,0,0,-1};
int dy[] = {0,-1,1,0};
int ans;
struct P{
  int f,s,sf,ss,c;
  P(int f,int s,int sf,int ss,int c):f(f),s(s),sf(sf),ss(ss),c(c) {};
};

  int bfs(){
    queue < P > que;
    que.push( P(tx,ty,kx,ky,0) );
    d[tx][ty][kx][ky] = true;

    int cnt = 0;
    while( !que.empty() ){
     P p = que.front(); que.pop();
     cnt++;

     if(cnt >= 100){
       ans = -1;
       break;
     }

     if(p.f == p.sf && p.s == p.ss) break;

      for(int i=0;i<4;i++){
	int ntx = p.f + dx[i];
	int nty = p.s + dy[i];
	int nkx = p.sf + dx[3-i];
	int nky = p.ss + dy[3-i];
	int c = p.c;
	ans = c;

	if(ntx < 1 || nty < 1 || ntx > w || nty > h || maze[nty][ntx] == 1){
	  ntx = p.f;
	  nty = p.s;
	}

	if(nkx < 1 || nky < 1 || nkx > w || nky > h || maze[nky][nkx] == 1){
	  nkx = p.sf;
	  nky = p.ss;
	}

	if(!d[ntx][nty][nkx][nky]) que.push( P(ntx,nty,nkx,nky,c+1) );
      }
    }
  }

int main(){

  while(true){
    cin >> w >> h;
    if(!w && !h) break;

    cin >> tx >> ty;
    cin >> kx >> ky;

    tx--; ty--; kx--; ky--;

    memset(maze,0,sizeof(maze));
    memset(d,false,sizeof(d));

    for(int i=0;i<h;i++){
      for(int j=0;j<w;j++) cin >> maze[i][j];
    }

    bfs();

    if(ans == -1) cout << "NA\n";
    else cout << ans << endl;
  }
}