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<bits/stdc++.h>
#define inf 1<<29
using namespace std;

class State{
public:
  int a,b,c,d;
  State(int a,int b,int c,int d):a(a),b(b),c(c),d(d){};
};

int h,w;
int table[51][51],memo[51][51][51][51];
int Y[4]={-1,0,1,0};
int X[4]={0,1,0,-1};

bool in(int a,int b){
  if(a<0 || b<0 || h<=a || w<=b)return false;
  return true;
}

void init(){
  for(int i=0;i<51;i++)
    for(int j=0;j<51;j++)
      for(int k=0;k<51;k++)
	for(int l=0;l<51;l++)memo[i][j][k][l]=inf;
}

int main()
{
  int a,b,c,d;
  while(1){
    cin>>w>>h;
    if(h+w==0)break;
    cin>>b>>a>>d>>c;
    a--;b--;c--;d--;
    for(int i=0;i<h;i++)for(int j=0;j<w;j++)cin>>table[i][j];
    init();

    queue<State> q;
    q.push(State(a,b,c,d));
    memo[a][b][c][d]=0;

    int ans=inf;
    while(!q.empty()){
      State u=q.front();
      q.pop();
      if(u.a==u.c && u.b==u.d){
	ans=min(memo[u.a][u.b][u.c][u.d],ans);
        break;
      }

      if(memo[u.a][u.b][u.c][u.d]>=100)continue;

      for(int i=0;i<4;i++){
	int A=u.a+Y[i],B=u.b+X[i],C=u.c+Y[(i+2)%4],D=u.d+X[(i+2)%4];
	if(!in(A,B))continue;
	if(!in(C,D))continue;
	if(table[A][B]){
	  A=u.a;
	  B=u.b;
	}
	if(table[C][D]){
	  C=u.c;
	  D=u.d;
	}
	if(memo[A][B][C][D]>memo[u.a][u.b][u.c][u.d]+1){
	  q.push(State(A,B,C,D));
	  memo[A][B][C][D]=memo[u.a][u.b][u.c][u.d]+1;
	}
      }
    }
    if(ans>=100)cout<<"NA"<<endl;
    else cout<<ans<<endl;
  }
  return 0;
}

C++: #include <bits/stdc++.h>
#define PB push_back
#define MP make_pair
#define REP(i,n) for (int i=0;i<(n);i++)
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define ALL(a) (a).begin(),(a).end()
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> P;
const int INF=1e9;
const int MOD=100000;
int B=1000000;
int dtx[4]={0,1,0,-1};
int dty[4]={1,0,-1,0};
int dkx[4]={0,-1,0,1};
int dky[4]={-1,0,1,0};
bool fld[50][50];
bool used[50][50][50][50];
struct A{int tx,ty,kx,ky,cnt;};
int X,Y;
bool pos(int x,int y){
      if(x<0||x>=X||y<0||y>=Y)return false;
      if(fld[x][y])return false;
      return true;
}
int main(){
      int tx,ty,kx,ky;
      while(cin>>X>>Y&&(X||Y)){
            int ans=-1;
            memset(used,false,sizeof(used));
            cin>>tx>>ty>>kx>>ky;tx--;ty--;kx--;ky--;
            REP(i,Y)REP(j,X)cin>>fld[j][i];
            queue<A>Q;
            Q.push((A){tx,ty,kx,ky,0});
            while(Q.size()){
                  A a=Q.front();Q.pop();
                  if(a.cnt>100)continue;
                  if(a.tx==a.kx&&a.ty==a.ky){
                        ans=a.cnt;
                        break;
                  }
                  //cout<<a.tx<<" "<<a.ty<<" "<<a.cnt<<" "<<a.kx<<" "<<a.ky<<endl;
                  REP(i,4){
                        int ntx=a.tx+dtx[i],nty=a.ty+dty[i];
                        int nkx=a.kx+dkx[i],nky=a.ky+dky[i];
                        if(!pos(ntx,nty)||!pos(nkx,nky)||used[ntx][nty][nkx][nky])continue;
                        used[ntx][nty][nkx][nky]=true;
                        Q.push((A){ntx,nty,nkx,nky,a.cnt+1});
                  }
            }
            if(ans==-1)cout<<"NA"<<endl;
            else cout<<ans<<endl;
      }
}

C++: // AOJ 0223
#include <iostream>
#include <queue>
#include <map>
#include <algorithm>

using namespace std;

#define x first
#define y second
#define mp make_pair

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

typedef pair <int, int> Point;
typedef pair <Point, Point> kotori;
int x, y;

ostream &operator<<(ostream &os, const Point &a) { os << "(" << a.x << ", " << a.y << ")"; return os; }

bool is_region(Point p)
{
	return (0 <= p.x && p.x < x && 0 <= p.y && p.y < y);
}

int main()
{
	while (cin >> x >> y, x || y){
		Point s1, s2;
		bool otonoki[64][64];
		cin >> s1.x >> s1.y;
		cin >> s2.x >> s2.y;
		s1.x--; s1.y--;
		s2.x--; s2.y--;
		for (int i = 0; i < y; i++){
			for (int j = 0; j < x; j++){
				cin >> otonoki[i][j];
			}
		}

		// cout << "in" << endl;

		map <kotori, bool> vst;
		queue <pair <kotori, int> > q;
		q.push(mp(mp(s1, s2), 0));
		bool f = false;
		while (!q.empty()){
			Point honoka = q.front().first.first, umi = q.front().first.second;
			int steps = q.front().second;
			q.pop();
			if (honoka == umi){
				cout << steps << endl;
				f = true;
				break;
			}
			if (vst[mp(honoka, umi)]) continue;
			vst[mp(honoka, umi)] = true;
			// cout << steps << " : " << honoka << " " << umi << endl;
			for (int i = 0; i < 4; i++){
				Point nh = honoka, nu = umi;
				nh.x += dx[i], nh.y += dy[i];
				nu.x -= dx[i], nu.y -= dy[i];

				// cout << nh << " " << nu << endl;
				// if (!is_region(nh) && !is_region(nu)) continue;
				if (vst[mp(nh, nu)]) continue;
				
				if (!is_region(nh)) nh.x -= dx[i], nh.y -= dy[i];
				if (!is_region(nu)) nu.x += dx[i], nu.y += dy[i];
				if (otonoki[nh.y][nh.x]) continue;
				if (otonoki[nu.y][nu.x]) continue;
				q.push(mp(mp(nh, nu), steps + 1));
			}
		}
		if (!f) cout << "NA" << endl;
	}

	return 0;
}