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 := 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<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);
        continue;
      }

      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(table[A][B] || !in(A,B)){
	  A=u.a;
	  B=u.b;
	}
	if(table[C][D] || !in(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 <iostream>
#include <queue>
using namespace std;

const int INF=100000000;

class Point{
public:
  int tx;
  int ty;
  int kx;
  int ky;
};

int main(){
  while(true){
    int X,Y;
    cin>>X>>Y;
    if(X==0&&Y==0){
      break;
    }
    char F[X+1][Y+1];
    int D[X+1][Y+1];
    for(int x=1;x<=X;x++){
      for(int y=1;y<=Y;y++){
        D[x][y]=INF;
      }
    }
    int tx,ty;
    cin>>tx>>ty;
    int kx,ky;
    cin>>kx>>ky;
    D[tx][ty]=0;
    D[kx][ky]=0;

    for(int x=0;x<=X+2;x++){
      for(int y=0;y<=Y+2;y++){
        F[x][y]=1;
      }
    }
    int a;
    for(int x=1;x<=X;x++){
      for(int y=1;y<=Y;y++){
        cin>>a;
        F[x][y]=a;
      }
    }

    queue<Point> que;

    Point p;
    p.tx=tx;
    p.ty=ty;
    p.kx=kx;
    p.ky=ky;
    que.push(p);

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

      if(p.tx==p.kx&&p.ty==p.ky){
        if(D[p.tx][p.ty]>100){
          cout<<"NA"<<endl;
          break;
        }
        cout<<D[p.tx][p.ty]<<endl;
        break;
      }

      if(D[p.tx-1][p.ty]==INF&&D[p.kx+1][p.ky]==INF){
        Point q;
        q.tx=p.tx-1;
        q.ty=p.ty;
        q.kx=p.kx+1;
        q.ky=p.ky;
        if(F[q.tx][q.ty]==1){
          q.tx=q.tx+1;
          D[q.tx][q.ty]=D[p.tx][p.ty]+1;
        }else
        if(F[q.kx][q.ky]==1){
          q.kx=q.kx-1;
          D[q.tx][q.ty]=D[p.tx][p.ty]+1;
        }else{
          D[q.tx][q.ty]=D[p.tx][p.ty]+1;
        }
        que.push(q);
      }

      if(D[p.tx+1][p.ty]==INF&&D[p.kx-1][p.ky]==INF){
        Point q;
        q.tx=p.tx+1;
        q.ty=p.ty;
        q.kx=p.kx-1;
        q.ky=p.ky;
        if(F[q.tx][q.ty]==1){
          q.tx=q.tx-1;
          D[q.tx][q.ty]=D[p.tx][p.ty]+1;
        }else
        if(F[q.kx][q.ky]==1){
          q.kx=q.kx+1;
          D[q.tx][q.ty]=D[p.tx][p.ty]+1;
        }else{
          D[q.tx][q.ty]=D[p.tx][p.ty]+1;
        }
        que.push(q);
      }

      if(D[p.tx][p.ty+1]==INF&&D[p.kx][p.ky-1]==INF){
        Point q;
        q.tx=p.tx;
        q.ty=p.ty+1;
        q.kx=p.kx;
        q.ky=p.ky-1;
        que.push(q);
        if(F[q.tx][q.ty]==1){
          q.ty=q.ty-1;
          D[q.tx][q.ty]=D[p.tx][p.ty]+1;
        }else
        if(F[q.kx][q.ky]==1){
          q.ky=q.ky+1;
          D[q.tx][q.ty]=D[p.tx][p.ty]+1;
        }else{
          D[q.tx][q.ty]=D[p.tx][p.ty]+1;
        }
        que.push(q);
      }

      if(D[p.tx][p.ty-1]==INF&&D[p.kx][p.ky+1]==INF){
        Point q;
        q.tx=p.tx;
        q.ty=p.ty-1;
        q.kx=p.kx;
        q.ky=p.ky+1;
        if(F[q.tx][q.ty]==1){
          q.ty=q.ty+1;
          D[q.tx][q.ty]=D[p.tx][p.ty]+1;
        }else
        if(F[q.kx][q.ky]==1){
          q.ky=q.ky-1;
          D[q.tx][q.ty]=D[p.tx][p.ty]+1;
        }else{
          D[q.tx][q.ty]=D[p.tx][p.ty]+1;
        }
        que.push(q);
      }

    }
  }

  return 0;
}