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<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;

  int cnt = 0;
  while( !que.empty() ){
    P p = que.front(); que.pop();

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

    cnt++;
    for(int i=0;i<4;i++){
      int ntx = p.f + dx[i];
      int nty = p.s + dy[i];
      int nkx = p.sf + dx[3-i];
      int nky = p.ss + dy[3-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(!d[ntx][nty][nkx][nky]){
	d[ntx][nty][nkx][nky] = true;
	que.push( P(ntx,nty,nkx,nky,p.c+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 <cstdlib>
#include <cmath>
#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <utility>
#include <set>
#include <map>
#include <stack>
#include <queue>
#include <functional>
#include <sstream>

using namespace std;

#define fst first
#define scd second
#define pb push_back
#define mp make_pair
#define chmin(a,b) a=min(a,b)
#define chmax(a,b) a=max(a,b)
#define rep(i,x) for(int i=0;i<(int)x;++i)
#define rep1(i,x) for(int i=1;i<=(int)x;++i)
#define rrep(i,x) for(int i=(int)x-1;i>=0;--i)
#define rrep1(i,x) for(int i=(int)x;i>=1;--i)
#define repf(i,a,x) for(int i=a;i<(int)x;++i)
#define repf1(i,a,x) for(int i=a;i<=(int)x;++i)
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()

template<typename T> T get(){T a;cin >> a;return a;}
template<typename T> T rev(T & a){reverse(all(a));return a;}

typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> pii;

const int inf = 1e9;
const ll linf = 1e18;

class P {
public:
    int x, y;
    P () {
        x = y = 0;
    };
    P (int x0,int y0) {
        x=x0,y=y0;
    };
};

int dx[4] = {-1, 0, 0, 1}, dy[4] = {0, -1, 1, 0};

int d[52][52];
int memo[52][52];
P coords[52][52];
bool used[52][52];

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

    int X, Y;
    while (cin >> X >> Y, X || Y) {
        int tx, ty; cin >> tx >> ty;
        int kx, ky; cin >> kx >> ky;
        fill(d[0], d[Y+2], 1);
        rep1(i, Y) rep1(j, X) cin >> d[i][j];

        queue<pair<P, P> > q;

        q.push(mp(P(tx, ty), P(kx, ky)));
        memo[ty][tx] = 0;

        int cnt = 0;

        while (q.size()) {
            if (cnt > 100) {
                break;
            }

            pair<P, P> r = q.front(); q.pop();
            P f = r.fst, s = r.scd;
            if (f.x == s.x && f.y == s.y) {
                cout << memo[r.fst.y][r.fst.x] << endl;
                goto nxt;
            }
            if (used[f.y][f.x]) continue;
            used[f.y][f.x] = true;

            rep(i, 4) {
                int nfx = f.x + dx[i], nfy = f.y + dy[i];
                int nsx = s.x - dx[i], nsy = s.y - dy[i];
                if (d[nfy][nfx] == 1 || d[nsy][nsx] == 1) continue;
                memo[nfy][nfx] = memo[f.y][f.x] + 1;
                q.push(mp(P(nfx, nfy), P(nsx, nsy)));
            }

            cnt++;
        }

        cout << "NA" << endl;

nxt:;
    }
}

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

struct State{
	pair<int,int> t,k;
	int turn;
};


int dy[]={0,1,0,-1};
int dx[]={1,0,-1,0};
int w,h;
int field[52][52];
bool visited[52][52][52][52];

int main(){
	while(cin>>w>>h,w|h){
		queue<State> q;
		State a,b;
		a.turn=0;
		cin>>a.t.second>>a.t.first;
		cin>>a.k.second>>a.k.first;
		for(int i=0;i<52;i++){
			for(int j=0;j<52;j++)field[i][j]=1;
		}
		for(int i=0;i<h;i++){
			for(int j=0;j<w;j++)cin>>field[i][j];
		}
		int ans=-1;
		q.push(a);
		visited[a.t.first][a.t.second][a.k.first][a.k.second]=true;
		while(!q.empty()){
			a=q.front();
			q.pop();
			if(a.t.first==a.k.first&&a.t.second==a.k.second){
				ans=a.turn;
				break;
			}
			if(100<a.turn+abs(a.t.first-a.k.first)+abs(a.t.second-a.k.second)){
				break;
			}
			for(int i=0;i<4;i++){
				b=a;
				b.t.first+=dy[i];
				b.t.second+=dx[i];
				b.k.first-=dy[i];
				b.k.second-=dx[i];
				if(field[b.t.first][b.t.second])b.t=a.t;
				if(field[b.k.first][b.k.second])b.k=a.k;
				b.turn=a.turn+1;
				if(!visited[b.t.first][b.t.second][b.k.first][b.k.second]){
					visited[b.t.first][b.t.second][b.k.first][b.k.second]=true;
					q.push(b);
				}
			}
		}
		if(ans==-1)cout<<"NA"<<endl;
		else cout<<ans<<endl;
	}
	return 0;
}