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 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]
			}
			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<stdio.h>
#include<iostream>
#include<queue>
#include<string.h>
using namespace std;
struct Y{
int hx,hy,rx,ry,tim;
};
int c[51][51][51][51];
int main(){
int n,w,h,i,j,a[2]={1,-1},b[2];
Y e;
while(cin>>w>>h&&w!=0&&h!=0){
int mp[52][52]={0};
queue<Y> q;
	cin>>e.hx>>e.hy>>e.rx>>e.ry;
	e.tim=0;
	q.push(e);
	memset(c,0,sizeof(c));
	for(i=0;i<=h+1;i++){
		mp[i][0]=1;
		mp[i][w+1]=1;
	}
	for(i=0;i<=w+1;i++){
		mp[0][i]=1;
		mp[h+1][i]=1;
	}
	for(i=1;i<=h;i++){
		for(j=1;j<=w;j++){
			cin>>mp[j][i];
		}
	}
	while(!q.empty()){
		e=q.front();
		q.pop();
		if(e.tim>=100||e.hx==e.rx&&e.hy==e.ry)break;
		e.tim++;
		for(i=0;i<2;i++){
			if(mp[e.hy+a[i]][e.hx]!=1&&c[e.hy+a[i]][e.hx][e.ry-a[i]][e.rx]==0&&mp[e.ry-a[i]][e.rx]!=1||mp[e.ry-a[i]][e.rx]!=1&&c[e.hy][e.hx][e.ry-a[i]][e.rx]==0&&mp[e.hy+a[i]][e.hx]==1||mp[e.hy+a[i]][e.hx]!=1&&mp[e.ry-a[i]][e.rx]==1&&c[e.hy+a[i]][e.hx][e.ry][e.rx]==0){
				b[0]=0;																										
				b[1]=0;																																		
				if(mp[e.hy+a[i]][e.hx]!=1){																											
					e.hy+=a[i];																																			
					b[0]=1;																																					
				}																																													
				if(mp[e.ry-a[i]][e.rx]!=1){																																										
					e.ry-=a[i];																																		
					b[1]=1;																																																														
				}		
				c[e.hy][e.hx][e.ry][e.rx]=1;																																																																																																																
				q.push(e);																											
				if(b[0]==1)e.hy-=a[i];																														
				if(b[1]==1)e.ry+=a[i];																											
			}																																																												
			if(mp[e.hy][e.hx+a[i]]!=1&&mp[e.ry][e.rx-a[i]]!=1&&c[e.hy][e.hx+a[i]][e.ry][e.rx-a[i]]==0||mp[e.hy][e.hx+a[i]]!=1&&c[e.hy][e.hx+a[i]][e.ry][e.rx]==0&&mp[e.ry][e.rx-a[i]]==1||mp[e.ry][e.rx-a[i]]!=1&&mp[e.hy][e.hx+a[i]]==1&&c[e.hy][e.hx][e.ry][e.rx-a[i]]==0){
				b[0]=0;
				b[1]=0;
				if(mp[e.hy][e.hx+a[i]]!=1){
					e.hx+=a[i];
					b[0]=1;
				}
				if(mp[e.ry][e.rx-a[i]]!=1){
					e.rx-=a[i];
					b[1]=1;
				}
				c[e.hy][e.hx][e.ry][e.rx]=1;
				q.push(e);
				if(b[0]==1)e.hx-=a[i];
				if(b[1]==1)e.rx+=a[i];
			}
		}
		e.tim--;
	}
	if(e.hy==e.ry&&e.hx==e.rx)cout<<e.tim<<endl;
	else printf("NA\n");
}
return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#include<stack>
#include<map>
#include<set>
#include<queue>
#include<cstdio>
#include<climits>
#include<cmath>
#include<cstring>
#include<string>
#include<sstream>
#include<numeric>
#include<cassert>

#define f first
#define s second
#define mp make_pair

#define REP(i,n) for(int i=0; i<(int)(n); i++)
#define rep(i,s,n) for(int i=(s); i<(int)(n); i++)
#define FOR(i,c) for(__typeof((c).begin()) i=(c).begin(); i!=(c).end(); i++)
#define ALL(c) (c).begin(), (c).end()
#define IN(x,s,g) ((x) >= (s) && (x) < (g))
#define ISIN(x,y,w,h) (IN((x),0,(w)) && IN((y),0,(h)))
#define print(x) printf("%d\n",x)

using namespace std;

typedef unsigned int uint;
typedef long long ll;

const int _dx[] = {0,1,0,-1};
const int _dy[] = {-1,0,1,0};

int getInt(){
  int ret = 0,c;
  c = getchar();
  while(!isdigit(c)) c = getchar();
  while(isdigit(c)){
    ret *= 10;
    ret += c - '0';
    c = getchar();
  }
  return ret;
}

int memo[52][52][52][52];

int main(){
  int w,h;
  while((w = getInt()) + (h = getInt())){
    int tx = getInt();
    int ty = getInt();
    int kx = getInt();
    int ky = getInt();

    w += 2; h += 2;
    vector<vector<int> > m(h, vector<int>(w, 1));

    REP(i,h-2) REP(j,w-2)
      m[i+1][j+1] = getInt();

    //REP(i,h){ REP(j,w) printf("%d ",m[i][j]); puts(""); }

    memset(memo, -1, sizeof(memo));

    typedef pair<pair<int,int>,pair<int,int> > data;
    queue<data> q;

#define MP(a,b,c,d) mp(mp(a,b),mp(c,d))
    q.push(MP(tx,ty,kx,ky));
    memo[tx][ty][kx][ky] = 0;

    while(!q.empty()){
      data d = q.front();

      int txx = d.f.f;
      int tyy = d.f.s;
      int kxx = d.s.f;
      int kyy = d.s.s;

      int now = memo[txx][tyy][kxx][kyy];

      if(now == 100) break;
      if(txx == kxx && tyy == kyy){
        printf("%d\n",memo[txx][tyy][kxx][kyy]);
        break;
      }

      //printf("%d,%d : %d,%d\n",txx,tyy,kxx,kyy);
      q.pop();

      REP(i,4){
        int txxx = txx + _dx[i];
        int tyyy = tyy + _dy[i];

        int kxxx = kxx - _dx[i];
        int kyyy = kyy - _dy[i];

        if(m[tyyy][txxx] == 1){
          txxx = txx;
          tyyy = tyy;
        }

        if(m[kyyy][kxxx] == 1){
          kxxx = kxx;
          kyyy = kyy;
        }

        if(memo[txxx][tyyy][kxxx][kyyy] == -1){
          memo[txxx][tyyy][kxxx][kyyy] = now + 1;
          q.push(MP(txxx,tyyy,kxxx,kyyy));
        }
      }
    }
    if(q.empty()){
      puts("NA");
    }
  }
  return 0;
}