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<iostream>
#include<queue>
using namespace std;
struct P{
  int tax, tay;
  int kax, kay;
  int c;

  P(int _tax, int _tay, int _kax, int _kay, int _c) : tax(_tax), tay(_tay), kax(_kax), kay(_kay), c(_c) {};
};

int x, y;
int m[51][51];
int tx, ty, kx, ky;

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

int bfs(void){
  queue<P> que;
  que.push(P(tx, ty, kx, ky, 0));

  bool a[51][51][51][51];

  for(int i = 0;i < x; i++)
    for(int j = 0;j < y; j++)
      for(int k = 0;k < x; k++)
	for(int l = 0;l < y; l++) a[i][j][k][l] = false;

  int ans = 100;

  while(que.size()){
    P p = que.front(); que.pop();
    if(p.tax == p.kax && p.tay == p.kay || p.c > 100){
      ans = p.c;
      break;
    }

    for(int i = 0;i < 4; i++){
      int nx1 = p.tax + dx[i], ny1 = p.tay + dy[i];
      int nx2 = p.kax - dx[i], ny2 = p.kay - dy[i];

      if((0 > nx1 || 0 > ny1 || nx1 >= x || ny1 >= y || m[ny1][nx1] == 1) && (0 > nx2 || 0 > ny2 || nx2 >= x || ny2 >= y || m[ny2][nx2] == 1)) continue;

      if(0 > nx1 || 0 > ny1 || nx1 >= x || ny1 >= y || m[ny1][nx1] == 1)      nx1 = p.tax, ny1 = p.tay;
      else if(0 > nx2 || 0 > ny2 || nx2 >= x || ny2 >= y || m[ny2][nx2] == 1) nx2 = p.kax, ny2 = p.kay;
 
      if(a[nx1][ny1][nx2][ny2]) continue;

      a[nx1][ny1][nx2][ny2] = true;

      que.push(P(nx1, ny1, nx2, ny2, p.c + 1));
    }
  }
  return ans;
}

int main(void){

  for( ; ; ){
    cin >> x >> y;

    if(!x && !y) break;

    cin >> tx >> ty >> kx >> ky;
    tx--; ty--; kx--; ky--;

    for(int i = 0;i < y; i++){
      for(int j = 0;j < x; j++){
	cin >> m[i][j];
      }
    }

    int ans = bfs();
    if(ans >= 100) cout << "NA" << endl;
    else cout << ans << endl;
  }
}

C++: #include <bits/stdc++.h>
using namespace std;
struct po{int x,y,a,b;};
int w,h;
int mp[51][51];
int tx,ty,kx,ky;
int dis[51][51][51][51];

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(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;
  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;

    }
}

C++: #include <queue>
#include <vector>
#include <cstring>
#include <iostream>
using namespace std;
int H, W, ax, ay, bx, by, x[52][52], dp[52][52][52][52];
int dx[4] = {0, 1, 0, -1}, dy[4] = {1, 0, -1, 0};
int main() {
	while(cin >> W >> H >> ax >> ay >> bx >> by) {
		for(int i = 0; i < H + 2; i++) {
			for(int j = 0; j < W + 2; j++) {
				x[i][j] = 1;
				if(i && i != H + 1 && j && j != W + 1) scanf("%d", &x[i][j]);
			}
		}
		memset(dp, -1, sizeof(dp)); dp[ay][ax][by][bx] = 0;
		queue<vector<int> > que; que.push({ax, ay, bx, by});
		bool flag = false;
		while(!que.empty()) {
			vector<int> v1 = que.front(); que.pop();
			for(int i = 0; i < 4; i++) {
				vector<int> v2 = v1;
				if(!x[v1[1] + dy[i]][v1[0] + dx[i]]) v2[0] += dx[i], v2[1] += dy[i];
				if(!x[v1[3] - dy[i]][v1[2] - dx[i]]) v2[2] -= dx[i], v2[3] -= dy[i];
				if(v2[0] == v2[2] && v2[1] == v2[3]) {
					flag = true; break;
				}
				if(dp[v2[1]][v2[0]][v2[3]][v2[2]] == -1) {
					dp[v2[1]][v2[0]][v2[3]][v2[2]] = dp[v1[1]][v1[0]][v1[3]][v1[2]] + 1;
					que.push(v2);
				}
			}
			if(flag) {
				cout << dp[v1[1]][v1[0]][v1[3]][v1[2]] + 1 << endl; break;
			}
		}
		if(!flag) cout << "NA" << endl;
	}
}

C++: #include<iostream>
#include<queue>
#include<string.h>
using namespace std;
#define rep(i,n) for(int i=0;i<n;i++)
#define rep1(i,n) for(int i=1;i<=n;i++)
struct X
{
int tx, ty, t, kx, ky;
};
int java[51][51][51][51] = { 0 };
int main()
{
int w, h, map[52][52] = { 0 };
int mx[4] = { 0,1,0,-1 }, my[4] = { 1,0,-1,0 };
while (1)
{
queue<X> que;
X c;
cin >> w >> h;
if (w == 0 && h == 0)
break;
memset(java, 0, sizeof(java));
memset(map,-1,sizeof(map));
cin >> c.tx >> c.ty >> c.kx >> c.ky;
c.t = 0;
que.push(c);
rep1(i, h)
{
rep1(j, w)
{
cin >> map[i][j];
}
}
while (!que.empty())
{
c = que.front();
que.pop();
java[c.tx][c.ty][c.kx][c.ky] = 1;
if (c.tx == c.kx&&c.ty == c.ky||c.t >= 100)
{
break;
}
c.t++;
rep(i, 4)
{
if (java[c.tx + mx[i]][c.ty + my[i]][c.kx - mx[i]][c.ky - my[i]] == 0 && map[c.tx + mx[i]][c.ty + my[i]] == 0 && map[c.kx - mx[i]][c.ky - my[i]] == 0)
{
c.tx += mx[i];
c.ty += my[i];
c.kx -= mx[i];
c.ky -= my[i];
que.push(c);
java[c.tx][c.ty][c.kx][c.ky] = 1;
c.tx -= mx[i];
c.ty -= my[i];
c.kx += mx[i];
c.ky += my[i];
}
else if (java[c.tx][c.ty][c.kx - mx[i]][c.ky - my[i]] == 0 && map[c.tx + mx[i]][c.ty + my[i]] != 0 && map[c.kx - mx[i]][c.ky - my[i]] == 0)
{
c.kx -= mx[i];
c.ky -= my[i];
que.push(c);
java[c.tx][c.ty][c.kx][c.ky] = 1;
c.kx += mx[i];
c.ky += my[i];
}
else if (java[c.tx + mx[i]][c.ty + my[i]][c.kx][c.ky] == 0 && map[c.tx + mx[i]][c.ty + my[i]] == 0 && map[c.kx - mx[i]][c.ky - my[i]] != 0)
{
c.tx += mx[i];
c.ty += my[i];
que.push(c);
java[c.tx][c.ty][c.kx][c.ky] = 1;
c.tx -= mx[i];
c.ty -= my[i];
}
}
}
if (c.tx==c.kx&&c.ky==c.ty)
cout << c.t << endl;
else
cout << "NA" << endl;
}
return 0;
}