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]
			}
			if now==next {
				continue
			}
			next.Turn += 1
			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 <vector>
#include <queue>
#include <cstring>

using namespace std;
class State
{
public:
  int x1,y1,x2,y2,cost;

  State(int tx1,int ty1,int tx2,int ty2,int tcost)
  {
    x1 = tx1;
    y1 = ty1;
    x2 = tx2;
    y2 = ty2;
    cost = tcost;
  }
};

int w,h;
bool t[52][52];
bool used[52][52][52][52];

int dx1[] = {-1,1,0,0};
int dx2[] = {1,-1,0,0};
int dy1[] = {0,0,1,-1};
int dy2[] = {0,0,-1,1};


void solve()
{
	while(cin>>w>>h && (w||h))
	{
    int x1,y1,x2,y2;
    cin>>x1>>y1>>x2>>y2;
    x1--; y1--; x2--; y2--;

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

    int ans = -1;
    queue<State> open;

    memset(used,0,sizeof(used));
    used[x1][y1][x2][y2] = true;
    open.push(State(x1,y1,x2,y2,0));

    while(!open.empty())
	{
      State st = open.front(); open.pop();
      if(st.cost >= 100) break;

      if(st.x1 == st.x2 && st.y1 == st.y2)
	  {
        ans = st.cost;
        break;
      }

      for(int i=0;i<4;i++)
	  {
        int nx1 = st.x1 + dx1[i];
        int ny1 = st.y1 + dy1[i];
        int nx2 = st.x2 + dx2[i];
        int ny2 = st.y2 + dy2[i];
        State nst = st;
        nst.cost++;

        if(nx1>=0 && nx1<w && ny1>=0 && ny1<h && !t[ny1][nx1])
		{
          nst.x1 = nx1;
          nst.y1 = ny1;
        }
        if(nx2>=0 && nx2<w && ny2>=0 && ny2<h && !t[ny2][nx2])
		{
          nst.x2 = nx2;
          nst.y2 = ny2;
        }

        if(!used[nst.x1][nst.y1][nst.x2][nst.y2])
		{
          used[nst.x1][nst.y1][nst.x2][nst.y2] = true;
          open.push(nst);
        }
      }
    }

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

}

int main()
{
	solve();
	return(0);
}

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

int x,y,tx,ty,kx,ky,cou;
int mas[111][111];
int ans=0;
bool used[111][111][111][111];
int dx[]={-1,0,0,1};
int dy[]={0,-1,1,0};
struct P{
  int tx,ty,kx,ky,cou;
  P(int tx,int ty,int kx,int ky,int cou):tx(tx),ty(ty),kx(kx),ky(ky),cou(cou){}
};
int bfs();

int main(){
  while(1){
    cin >> x >> y;
    if(x==0 && y==0) break;
    memset(used,false,sizeof(used));
    cin >> tx >> ty;
    cin >> kx >> ky;
    for(int i=0;i<y;i++){
      for(int j=0;j<x;j++){
	cin >> mas[i][j];
      }
    }
    ans = bfs();
    if(ans==-1) cout << "NA" << endl;
    else cout << ans << endl;
  }
}

int bfs(){
  queue<P> que;
  que.push(P(tx-1,ty-1,kx-1,ky-1,0));
  used[tx-1][ty-1][kx-1][ky-1] = true;
  while(!que.empty()){
    P p=que.front();
    if(p.tx==p.kx && p.ty==p.ky) return p.cou;
    else if(p.cou>=100) return -1;
    for(int i=0;i<4;i++){
      int ntx=p.tx+dx[i];
      int nty=p.ty+dy[i];
      int nkx=p.kx+dx[3-i];
      int nky=p.ky+dy[3-i];
      if(ntx<0 || ntx>=x || nty<0 || nty>=y || mas[nty][ntx]==1){
	ntx=p.tx;
	nty=p.ty;
      }
      if(nkx<0 || nkx>=x || nky<0 || nky>=y || mas[nky][nkx]==1){
	nkx=p.kx;
	nky=p.ky;
      }
      if(used[ntx][nty][nkx][nky]==false){
	que.push(P(ntx,nty,nkx,nky,p.cou+1));
	used[ntx][nty][nkx][nky] = true;
      }
    }
    que.pop();
  }
  return -1;
}