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 <bits/stdc++.h>
using namespace std;
typedef long long ll;

const int INF = 1 << 25;
int dx[4] = { 1, 0, -1, 0 }, dy[4] = { 0, 1, 0, -1 };

int b[50][50];
int dist[50][50][50][50];

int W, H;

struct S {
	int x1, y1, x2, y2, d;
};

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

	while(cin >> W >> H, W + H) {
		int sx[2], sy[2];
		for(int i = 0; i < 2; i++) {
			cin >> sx[i] >> sy[i];
			sx[i]--, sy[i]--;
		}
		for(int i = 0; i < H; i++) {
			for(int j = 0; j < W; j++) {
				cin >> b[i][j];
			}
		}

		fill((int*)begin(dist), (int*)end(dist), INF);
		dist[sy[0]][sx[0]][sy[1]][sx[1]];
		queue<S> q;
		q.push({ sx[0], sy[0], sx[1], sy[1], 0 });
		while(q.size()) {
			int x[2] = { q.front().x1, q.front().x2 };
			int y[2] = { q.front().y1, q.front().y2 };
			int d = q.front().d;
			q.pop();
			if(d == 99) break;
			if(dist[y[0]][x[0]][y[1]][x[1]] < d) continue;
			for(int k = 0; k < 4; k++) {
				int nx[2] = { x[0] + dx[k], x[1] - dx[k] };
				int ny[2] = { y[0] + dy[k], y[1] - dy[k] };
				for(int i = 0; i < 2; i++) {
					if(nx[i] < 0 || W <= nx[i] || b[ny[i]][nx[i]]) nx[i] = x[i];
					if(ny[i] < 0 || H <= ny[i] || b[ny[i]][nx[i]]) ny[i] = y[i];
				}
				if(dist[ny[0]][nx[0]][ny[1]][nx[1]] > d + 1) {
					dist[ny[0]][nx[0]][ny[1]][nx[1]] = d + 1;
					q.push({ nx[0], ny[0], nx[1], ny[1], d + 1 });
				}
			}
		}

		int ans = INF;
		for(int y = 0; y < H; y++) {
			for(int x = 0; x < W; x++) {
				ans = min(ans, dist[x][y][x][y]);
			}
		}
		if(ans != INF) {
			cout << ans << endl;
		}
		else {
			cout << "NA" << endl;
		}
	}
}

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;
}