Go: package main

import (
	"container/heap"
	"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)
	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)
	dx := []int64{0, 1, 0, -1}
	dy := []int64{1, 0, -1, 0}
	memo := make(map[PersonPosition]struct{}, 0)
	for pq.Len() > 0 {
		now := heap.Pop(&pq).(*Status)
		if now.Person.Distance() == 0 {
			fmt.Println(now.Turn)
			return
		}
		if _, ok := memo[now.Person]; ok {
			continue
		}
		memo[now.Person] = struct{}{}
		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 += 1
			if next.Turn < 100 {
				heap.Push(&pq, next)
			}
		}
	}
	fmt.Println("NA")
}

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<map>
using namespace std;
const int INF=(1<<21);
typedef pair<int,int> P;
int x,y;
int tx,ty;
int kx,ky;
int t_check[50][50];
int k_check[50][50];
int depart[50][50];
int dx[]={1,0,-1,0},dy[]={0,-1,0,1};
int ans=0;

int bfs(){
  queue<P> t_que;
  queue<P> k_que;

  for(int i=0;i<y;i++){
    for(int j=0;j<x;j++){
      t_check[i][j]=k_check[i][j]=INF;
    }
  }

  t_check[ty-1][tx-1]=0;
  k_check[ky-1][kx-1]=0;

  t_que.push(P(ty-1,tx-1));
  k_que.push(P(ky-1,kx-1));

  while(t_que.size()){
    P tp=t_que.front();t_que.pop();
    P kp=k_que.front();k_que.pop();
    if(tp.first==kp.first && tp.second==kp.second){
      return t_check[tp.first][tp.second];
    }

    for(int i=0;i<4;i++){
      int tnx=tp.second+dx[i];
      int tny=tp.first+dy[i];
      int knx=kp.second-(dx[i]);
      int kny=kp.first-(dy[i]);

      if(0<=tnx && tnx<x && 0<=tny && tny<y && depart[tny][tnx]!=1 && t_check[tny][tnx]==INF  &&  0<=knx && knx<x && 0<=kny && kny<y && depart[kny][knx]!=1 && k_check[kny][knx]==INF){

	t_que.push(P(tny,tnx));
	k_que.push(P(kny,knx));
	t_check[tny][tnx]=t_check[tp.first][tp.second]+1;
	k_check[kny][knx]=k_check[kp.first][kp.second]+1;

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

C++: #include<iostream>
#include<queue>
#include<map>
using namespace std;
const int INF=(1<<21);
typedef pair<int,int> P;
int x,y;
int tx,ty;
int kx,ky;
int t_check[50][50];
int k_check[50][50];
int depart[50][50];
int dx[]={1,0,-1,0},dy[]={0,-1,0,1};
int ans=0;

int bfs(){
  queue<P> t_que;
  queue<P> k_que;

  for(int i=0;i<y;i++){
    for(int j=0;j<x;j++){
      t_check[i][j]=k_check[i][j]=INF;
    }
  }

  t_check[ty-1][tx-1]=0;
  k_check[ky-1][kx-1]=0;

  t_que.push(P(ty-1,tx-1));
  k_que.push(P(ky-1,kx-1));

  while(t_que.size()){
    P tp=t_que.front();t_que.pop();
    P kp=k_que.front();k_que.pop();
    if(tp.first==kp.first && tp.second==kp.second){
      return t_check[tp.first][tp.second];
    }

    for(int i=0;i<4;i++){
      int tnx=tp.second+dx[i];
      int tny=tp.first+dy[i];
      int knx=kp.second-(dx[i]);
      int kny=kp.first-(dy[i]);

      if(0<=tnx && tnx<x && 0<=tny && tny<y && depart[tny][tnx]!=1 && t_check[tny][tnx]==INF  &&  0<=knx && knx<x && 0<=kny && kny<y && depart[kny][knx]!=1 && k_check[kny][knx]==INF){

	t_que.push(P(tny,tnx));
	k_que.push(P(kny,knx));
	t_check[tny][tnx]=t_check[tp.first][tp.second]+1;
	k_check[kny][knx]=k_check[kp.first][kp.second]+1;

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

C++: #include<iostream>
#include<cstdio>
#include<queue>
#include<map>
#include<algorithm>
#include<cstring>
#include<string>
using namespace std;
struct P{
  int tx,ty;
  int kx,ky;
  int cost;
  P(int _tx, int _ty, int _kx, int _ky, int _cost) : tx(_tx), ty(_ty), kx(_kx), ky(_ky), cost(_cost) {};
};
int hx,hy,rx,ry;
int X,Y;
int mas[110][110];
bool d[51][51][51][51];
int dx[4] = {0,1,0,-1},dy[4] = {1,0,-1,0};
int bfs();
int main(){
  while(1){
    scanf("%d %d",&X,&Y);
    if(X == 0 && Y == 0)break;
    scanf("%d %d",&hx,&hy);
    scanf("%d %d",&rx,&ry);
    for(int i = 1; i <= Y; i++){
      for(int j = 1; j <= X; j++){
	scanf("%d",&mas[i][j]);
      }
    }
    int ans = bfs();
    if(ans == -1)cout << "NA" << endl;
    else cout << ans << endl;
  }
}
int bfs(){
  queue<P> que;
  memset(d,0,sizeof(d));
  que.push(P(hx,hy,rx,ry,0));
  d[hx][hy][rx][ry] = 0;
  while(!que.empty()){
    P p = que.front();
    que.pop();
    if(p.cost >= 100)return -1;
    if(p.tx == p.kx && p.ty == p.ky){
      return p.cost;
    }
    for(int i = 0; i < 4; i++){
      int nx = p.tx + dx[i], ny = p.ty + dy[i];
      int ux = p.kx - dx[i], uy = p.ky - dy[i];
      if(nx > 0 && ny > 0 && ux > 0 && uy > 0 && nx <= X && ny <= Y && ux <= X && uy <= Y && mas[ny][nx] != 1 && mas[uy][ux] != 1 && d[nx][ny][ux][uy] == 0){
	que.push(P(nx,ny,ux,uy,p.cost++));
	d[nx][ny][ux][uy] =  1;
      }
      else if((nx <= 0 || nx > X || ny <= 0 || ny > Y || mas[ny][nx] == 1) && ux <= X && uy <= Y && ux > 0 && uy > 0 && mas[uy][ux] != 1 && d[p.tx][p.ty][ux][uy] == 0){
	que.push(P(p.tx,p.ty,ux,uy,p.cost++));
	d[p.tx][p.ty][ux][uy] = 1;
      }
      else if((ux <= 0 || ux > X || uy <= 0 || uy > Y || mas[uy][ux] == 1) && nx <= X && ny <= Y && nx > 0 && ny > 0 && mas[ny][nx] != 1 && d[nx][ny][p.kx][p.ky] == 0){
	que.push(P(nx,ny,p.kx,p.ky,p.cost++));
	d[nx][ny][p.kx][p.ky] = 1;
      }
    }
  }
  return -1;
}