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<queue>
#include<cstring>
using namespace std;

int w,h;
int tx,ty;
int kx,ky;
int maze[100][100]; //y,x
bool d[55][55][55][55];
int dx[] = {1,0,0,-1};
int dy[] = {0,1,-1,0};
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;

  while( !que.empty() ){
    P p = que.front(); que.pop();

    if(p.c == 100) return -1;
    if(p.f == p.sf && p.s == p.ss) return p.c;

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


      if(ntx < 0 || nty < 0 || ntx == w || nty == h || maze[nty][ntx] == 1){
	ntx = p.f;
	nty = p.s;
      }

      if(nkx < 0 || nky < 0 || nkx == w || nky == h || maze[nky][nkx] == 1){
	nkx = p.sf;
	nky = p.ss;
      }

      if(ntx == p.f && nty == p.s && nkx == p.sf && nky == p.ss) continue;

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

    }
  }

  return -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];
    }

    int ans = bfs();

    if(ans < 0) cout << "NA\n";
    else cout << ans << endl;

  }
}

C++: #include <cstdio>
#include <queue>
#include <map>
#include <algorithm>
using namespace std;
typedef pair<int,int> pii;
typedef tuple<pii,pii,int> T;
int M[51][51],dx[]={-1,0,1,0},dy[]={0,-1,0,1};
int main(){
	int a,b,x,y,X,Y,i,j;
	for(;scanf("%d%d",&a,&b),a;){
		map<pair<pii,pii>,int>m;
		scanf("%d%d%d%d",&x,&y,&X,&Y);x--,y--,X--,Y--;
		for(j=0;j<b;j++)for(i=0;i<a;i++)scanf("%d",M[i]+j);
		queue<T>q;
		m[make_pair(make_pair(x,y),make_pair(X,Y))]=1;
		for(q.push(make_tuple(make_pair(x,y),make_pair(X,Y),0));!q.empty();){
			T z=q.front();q.pop();
			if(get<0>(z)==get<1>(z)){printf("%d\n",get<2>(z));goto OK;}
			if(get<2>(z)>=99)continue;
			for(i=0;i<4;i++){
				pii c1=make_pair(get<0>(z).first+dx[i],get<0>(z).second+dy[i]);
				if(!(0<=c1.first&&c1.first<a&&0<=c1.second&&c1.second<b&&!M[c1.first][c1.second]))c1=get<0>(z);
				pii c2=make_pair(get<1>(z).first+dx[(i+2)%4],get<1>(z).second+dy[(i+2)%4]);
				if(!(0<=c2.first&&c2.first<a&&0<=c2.second&&c2.second<b&&!M[c2.first][c2.second]))c2=get<1>(z);
				if((c1!=get<0>(z)||c2!=get<1>(z))&&!m[make_pair(c1,c2)]){
					q.push(make_tuple(c1,c2,get<2>(z)+1));
					m[make_pair(c1,c2)]=1;
				}
			}
		}
		puts("NA");
		OK:;
	}
}