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 (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)
	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)
	pq.Push(start)
	dx := []int64{0, 1, 0, -1}
	dy := []int64{1, 0, -1, 0}
	memo := make(map[PersonPosition]int64, 0)
	ans := int64(101)
	for pq.Len() > 0 {
		//now := heap.Pop(&pq).(*Status)
		now := pq.Pop().(*Status)
		if now.Person.Distance() == 0 && ans > now.Turn {
			ans = now.Turn
		}
		if ans <= now.Turn {
			continue
		}
		if v, ok := memo[now.Person]; ok && v <= now.Turn {
			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 += 1
			if next.Turn < 100 {
				//heap.Push(&pq, next)
				pq.Push(next)
			}
		}
	}
	if ans == 101 {
		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<queue>
#include<iostream>
#include<algorithm>
using namespace std;
struct maigo{
	int x[2];// ????????????[0]???????????????[1]
	int y[2];// ????????????[0]???????????????[1]
	int count;
};
int main(){
	queue<maigo> q;
	int tx, ty; int kx, ky;
	int **depart, X, Y;
	int flag = 0, a = 0;
	cin >> X >> Y;
	while (X != 0 && Y != 0){
		depart = new int*[Y + 2];
		for (int i = 0; i < Y + 2; i++){
			depart[i] = new int[X + 2];
		}
		for (int i = 0; i < Y + 2; i++){
			for (int l = 0; l < X + 2; l++){
				depart[i][l] = 3;
			}
		}
		cin >> tx >> ty;
		cin >> kx >> ky;
		for (int i = 1; i < Y + 1; i++){
			for (int l = 1; l < X + 1; l++){
				cin >> depart[i][l];
			}
		}
		maigo temp;
		temp.x[0] = tx; temp.y[0] = ty;
		temp.x[1] = kx; temp.y[1] = ky;
		temp.count = 1;
		q.push(temp);
		while (!q.empty() && flag == 0){
			maigo t = q.front();
			q.pop();
			int dx1[4] = { 1, 0, -1, 0 }; int dx2[4] = { 0, 1, 0, -1 };
			for (int i = 0; i < 4; i++){
				if (depart[t.x[0] + dx1[i]][t.y[0] + dx2[i]] == 0 &&
					depart[t.x[1] + dx1[i] * (-1)][t.y[1] + dx2[i] * (-1)] == 0){
					depart[t.x[0] + dx1[i]][t.y[0] + dx2[i]] = -1;
					depart[t.x[1] + dx1[i] * (-1)][t.y[1] + dx2[i] * (-1)] = -1;
					if (t.x[0] + dx1[i] == t.x[1] + dx1[i] * (-1) &&
						t.y[0] + dx2[i] == t.y[1] + dx2[i] * (-1)){
						cout << t.count << endl;
						flag = 1;
					}
					maigo into;
					into.x[0] = t.x[0] + dx1[i], into.y[0] = t.y[0] + dx2[i];
					into.x[1] = t.x[1] + dx1[i] * (-1), into.y[1] = t.y[1] + dx2[i] * (-1);
					into.count = t.count + 1;
					if (into.count >= 100){
						flag = 1;
						a = 1;
					}
					q.push(into);
				}
			}
		}if (a == 1||flag == 0) {
			cout << "NA" << endl;
		}while (!q.empty()) q.pop();
		a = 0; flag = 0;
		cin >> X >> Y;
	}
	return 0;
}

C++: #include<cstdio>
#include<iostream>
#include<string>
#include<map>
#include<queue>
#include<set>

using namespace std;

#define rep(i,n) for(int i=0;i<n;i++)
#define reps(i,n) for(int i=1;i<=n;i++)

class S{
	public:
	char a,b,c,d;
	int val;
	S(int a,int b,int c,int d,int val):
	a(a),b(b),c(c),d(d),val(val){}
};

char ch[55][55][55][55];

int main(){
	while(1){
		int n,m;
		cin>>n>>m;
		if(n==0)break;
		
		int sa,sb,sc,sd;
		cin>>sa>>sb>>sc>>sd;
		
		int masu[55][55];
		rep(i,n){
			rep(j,m){
				cin>>masu[i][j];
			}
		}
		
		rep(i,55)rep(j,55)rep(k,55)rep(p,55)ch[i][j][k][p]=0;
		
		queue<S> que;
		que.push(S(sb,sa,sd,sc,0));
		
		int dx[4]={-1,0,1,0};
		int dy[4]={0,1,0,-1};
		
		int ans=-1;
		while(1){
			if(que.empty())break;
			
			S u = que.front();
			que.pop();
			
			
			if(u.a<=0 || u.b<=0 || u.c<=0 || u.d<=0)continue;
			if(u.a>m || u.c>m || u.b>n || u.d>n)continue;
			
			if(ch[u.a][u.b][u.c][u.d]==1)continue;
			ch[u.a][u.b][u.c][u.d]=1;
			
			
			if(u.a == u.c && u.b==u.d){
				ans = u.val;
				break;
			}
			
			S e = u;
			e.val++;
			rep(i,4){
				e.a += dx[i];
				e.b += dy[i];
				rep(j,4){
					e.c += dx[j];
					e.d += dy[j];
					
					if(masu[e.a][e.b]==1 || masu[e.c][e.d]==1){
					}else if(ch[u.a][u.b][u.c][u.d]==1){
					}else{
						que.push(e);
					}
					
					e.c -= dx[j];
					e.d -= dy[j];
				}
				e.a -= dx[i];
				e.b -= dy[i];
			}
		}
		printf("%d\n",ans);
	}
}

C++: #include <bits/stdc++.h>
using namespace std;
struct po{int x,y,a,b;};
int w,h;
int mp[55][55];
int tx,ty,kx,ky;
int dis[55][55][55][55];

po mkp(int a,int b,int c,int d){
  po res;
  res.x=a, res.y=b, res.a=c,res.b=d;
  return res;
}

int bfs(){
  int dx[]={0,0,-1,1};
  int dy[]={1,-1,0,0};
  memset(dis,0,sizeof(dis));
  queue <po> Q;
  Q.push(mkp(tx,ty,kx,ky));

  while(!Q.empty()){
    po t=Q.front();Q.pop();

    if(dis[t.y][t.x][t.b][t.a]>=100) return -1;
    if(t.x==t.a&&t.y==t.b) return dis[t.y][t.x][t.b][t.a];
    

    for(int i=0;i<4;i++){
      int nx=t.x+dx[i],ny=t.y+dy[i];
      int na=t.a-dx[i],nb=t.b-dy[i];
      if(nx<0||ny<0||nx>=w||ny>=h||mp[ny][nx])nx=t.x,ny=t.y;
      if(na<0||nb<0||na>=w||nb>=h||mp[nb][na])na=t.a,nb=t.b;
      if(nx==t.x&&ny==t.y&&na==t.a&&nb==t.b)continue;
      if(dis[ny][nx][nb][na])continue;
      dis[ny][nx][nb][na]=dis[t.y][t.x][t.b][t.a]+1;
      Q.push(mkp(nx,ny,na,nb));
    }
  }
  return -1;
}

int main(){

  while(1){
  cin>>w>>h;
  if(!w&&!h)break;
  cin>>tx>>ty>>kx>>ky;
  tx--,ty--,kx--,ky--;
  for(int i=0;i<h;i++)
    for(int j=0;j<w;j++) cin>>mp[i][j];
  int res=bfs();
  if(res==-1) cout << "NA"<<endl;
  else cout <<res<<endl;
  }
  return 0;
}