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<iostream>
#include<algorithm>
#include<queue>
using namespace std;

bool d[50][50][50][50];
int X, Y, tx, ty, kx, ky;
int dx[] = {0, 0, 1, -1}, dy[] = {1, -1, 0, 0}, mem[50][50];

bool _check(int x, int y)
{
  return x >= 0 && x < X && y >= 0 && y < Y;
}

bool check(int x1, int y1, int x2, int y2)
{
  return _check(x1, y1) && _check(x2, y2);
}

int main()
{
loop:
  cin >> X >> Y;
  if(!X)
    return 0;
  cin >> tx >> ty >> kx >> ky;
  tx--; ty--; kx--; ky--;
  for(int y = 0; y < Y; y++)
  {
    for(int x = 0; x < X; x++)
    {
      int a;
      cin >> a;
      mem[y][x] = a;
    }
  }

  fill_n((bool*)d, 50 * 50 * 50 * 50, false);
  
  queue<int> q;
  q.push(tx);
  q.push(ty);
  q.push(kx);
  q.push(ky);
  q.push(0);
  while(!q.empty())
  {
    int x1 = q.front(); q.pop();
    int y1 = q.front(); q.pop();
    int x2 = q.front(); q.pop();
    int y2 = q.front(); q.pop();
    int n = q.front(); q.pop();
    
    if(n >= 100)
    {
      cout << "NA" << endl;
      break;
    }
    
    if(y1 == y2 && x1 == x2)
    {
      cout << n << endl;
      goto loop;
    }

    for(int i = 0; i < 4; i++)
    {
      int tx1 = x1 + dx[i];
      int ty1 = y1 + dy[i];
      int tx2 = x2 - dx[i];
      int ty2 = y2 - dy[i];

      if(check(tx1, ty1, tx2, ty2) && mem[ty1][tx1])
      {
        tx1 = x1;
        ty1 = y1;
      }
      if(check(tx1, ty1, tx2, ty2) && mem[ty2][tx2])
      {
        tx2 = x2;
        ty2 = y2;
      }
      if(!check(tx1, ty1, tx2, ty2) || d[tx1][ty1][tx2][ty2])
        continue; 

      d[tx1][ty1][tx2][ty2] = true;
      q.push(tx1);
      q.push(ty1);
      q.push(tx2);
      q.push(ty2);
      q.push(n + 1);
    }
  }
  cout << "NA" << endl;
  goto loop;
}

C++: #include<queue>
#include<iostream>
#include<algorithm>
#include<cstring>
#include<cstdio>
using namespace std;
int dy[]={1,-1,0,0};
int dx[]={0,0,1,-1};
// 構造体
struct P{
  int ty;
  int tx;
  int ky;
  int kx;
  int c;
  P(int ty,int tx,int ky,int kx,int c):ty(ty),tx(tx),ky(ky),kx(kx),c(c){}
};
int bfs(int ty,int tx,int ky,int kx);
int g[51][51];
int d[51][51][51][51]; // フラグ
int x,y;
int main(){
  int tx,ty;
  int kx,ky;
  while(1){
    cin >> x >> y;
    if(!x && !y)break;
    cin >> tx >> ty;
  cin >> kx >> ky;
  for(int i=0;i<y;i++){
    for(int j=0;j<x;j++){
      cin >> g[i][j];
    }
  }
  int ret = bfs( ty - 1 , tx - 1 , ky - 1 , kx - 1 );
  if(ret != -1){
    cout << ret << endl;
  }else {
    cout << "NA" << endl;
  }
    memset( d , 0 , sizeof(d) );
  }
}
int bfs(int ty,int tx,int ky,int kx){
  queue<P> que;
  que.push(P(ty,tx,ky,kx,0));
  d[ty][tx][ky][kx] = 1;

  while(!que.empty()){
    P p = que.front();que.pop();
    // 終了判定
    if(p.c > 100)return -1;
    if(p.ty == p.ky && p.tx == p.kx)return p.c;
     for(int i=0;i<4;i++){
      int tty = p.ty + dy[i];
      int ttx = p.tx + dx[i];
      int kky = p.ky + (dy[i] * -1); // 　↓
      int kkx = p.kx + (dx[i] * -1); // 逆方向

      // 両方いけるとき
      if(0<=tty && tty<y && 0<=ttx && ttx<x){
        if(0<=kky && kky<y && 0<=kky && kkx<x){
          if(d[tty][ttx][kky][kkx] == 0  && g[tty][ttx] == 0 && g[kky][kkx] == 0){
            que.push(P(tty,ttx,kky,kkx,p.c+1));
            d[tty][ttx][kky][kkx] = 1;
          }
        }
      }
      // たかゆきくんだけいけるとき
      if(0<=tty && tty<y && 0<=ttx && ttx<x){
        if(0>kky || kky>=y || 0>kky || kkx>=x || g[kky][kkx] == 1){
          if(d[tty][ttx][p.ky][p.kx] == 0 && g[tty][ttx] == 0){
            que.push(P(tty,ttx,p.ky,p.kx,p.c+1));
            d[tty][ttx][p.ky][p.kx] = 1;
          }
        }
      }
      // 一之君だけいけるとき
       if(0<=kky && kky<y && 0<=kkx && kkx<x){
        if(0>tty || tty>=y || 0>tty || ttx>=x || g[tty][ttx] == 1){
          if(d[p.ty][p.tx][kky][kkx] == 0 && g[kky][kkx] == 0){
            que.push(P(p.ty,p.tx,kky,kkx,p.c+1));
            d[p.ty][p.tx][kky][kkx] = 1;
          }
        }
      }
    }
  }
  return -1;
}