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)
	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.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 {
		heap.Init(&pq)
		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;
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++){
        cin >> F[y][x];
      }
    }
    for(int y=1;y<=H;y++){
      for(int x=1;x<=W;x++){
        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 <queue>

using namespace std;

#define fst first
#define scd second
#define mp make_pair
#define rep(i,x) for(int i=0;i<(int)x;++i)
#define rep1(i,x) for(int i=1;i<=(int)x;++i)

class P {
public:
    int x, y;
    P () {
        x = y = 0;
    };
    P (int x0,int y0) {
        x=x0,y=y0;
    };
};

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

int d[53][53];
int memo[53][53][53][53];
bool used[53][53][53][53];

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);

    int X, Y;
    while (cin >> X >> Y, X || Y) {
        int tx, ty; cin >> tx >> ty;
        int kx, ky; cin >> kx >> ky;
        fill(d[0], d[Y+2], 1);
        rep1(i, Y) rep1(j, X) cin >> d[i][j];

        queue<pair<P, P> > q;

        q.push(mp(P(tx, ty), P(kx, ky)));
        memo[ty][tx][ky][kx] = 0;
        used[ty][tx][ky][kx] = true;

        int ans = -1;

        while (q.size()) {
            pair<P, P> r = q.front(); q.pop();
            P f = r.fst, s = r.scd;

            if (memo[f.y][f.x][s.y][s.x] >= 100) break;

            if (f.x == s.x && f.y == s.y) {
                ans = memo[f.y][f.x][s.y][s.x];
                break;
            }

            rep(i, 4) {
                int nfx = f.x + dx[i], nfy = f.y + dy[i];
                int nsx = s.x - dx[i], nsy = s.y - dy[i];
                if (d[nfy][nfx] == 1) nfx = f.x, nfy = f.y;
                if (d[nsy][nsx] == 1) nsx = s.x, nsy = s.y;
                if (!used[nfy][nfx][nsy][nsx]) {
                    used[nfy][nfx][nsy][nsx] = true;
                    memo[nfy][nfx][nsy][nsx] = memo[f.y][f.x][s.y][s.x] + 1;
                    q.push(mp(P(nfx, nfy), P(nsx, nsy)));
                }
            }
        }

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