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>
#include <cstring>
using namespace std;


int H,W;
bool F[52][52]; //障害物
bool D[52][52][52][52]; //探索済みかの判定用

class Point{
public:
  int tx; //タカユキの座標
  int ty;
  int kx; //カズユキの座標
  int ky;
  int d; //ターン回数
  void set(int a,int b,int c,int d){
    tx = a;
    ty = b;
    kx = c;
    ky = d;
  }
};

bool is_out_of_area(int y,int x) //座標が範囲内か確認する関数
{
  return x < 1 || x > W || y < 1 || y > H || F[y][x];
}

int main(){

  while(1){

    Point p,q;
    int tx,ty,kx,ky;
    queue<Point> qa;
    cin >> W >> H;
    if(W == 0 && H == 0)
    break;
    cin >> tx >> ty >> kx >> ky;
    memset(F,1,sizeof(F));
    for(int y=1;y<=H;y++){
      for(int x=1;x<=W;x++){
        cin >> F[y][x];
      }
    }
    memset(D,1,sizeof(D));
    p.set(tx,ty,kx,ky);
    D[ty][tx][ky][kx] = 0;
    p.d = 0;
    qa.push(p);
    while(1){
      int inc_tx,inc_ty,inc_kx,inc_ky;
      if(qa.empty()){
        cout << "NA" <<endl;
        break;
      }
      p = qa.front();
      qa.pop();
      if(p.d >= 100){
        cout << "NA" << endl;
        break;
      }
      if(p.tx == p.kx && p.ty == p.ky){
        cout << p.d << endl;
        break;
      }

      if(D[p.ty-1][p.tx][p.ky+1][p.kx]){ //タカユキの y 座標を-1, カズユキを+1 同様の if 文が下に四つ続く

        inc_ty = -1 ; inc_ky = 1;
        if(is_out_of_area(p.ty-1,p.tx)){ //範囲外または障害物にあたったならば移動しない
          inc_ty = 0;
        }
        if(is_out_of_area(p.ky+1,p.kx)){ //範囲外または障害物にあたったならば移動しない
          inc_ky = 0;
        }
        if(inc_ty || inc_ky){ //どちらかが動ける状態であったならキューにプッシュ
          q.set(p.tx,p.ty + inc_ty,p.kx,p.ky+inc_ky);
          q.d = p.d + 1;
          qa.push(q);
          D[q.ty][q.tx][q.ky][q.kx] = 0;
        }

      }

      if(D[p.ty+1][p.tx][p.ky-1][p.kx]){
        inc_ty = 1 ; inc_ky = -1;
        if(is_out_of_area(p.ty+1,p.tx)){
          inc_ty = 0;
        }
        if(is_out_of_area(p.ky-1,p.kx)){
          inc_ky = 0;
        }
        if(inc_ty || inc_ky){
          q.set(p.tx,p.ty + inc_ty,p.kx,p.ky+inc_ky);
          q.d = p.d + 1;
          qa.push(q);
          D[q.ty][q.tx][q.ky][q.kx] = 0;
        }
      }

      if(D[p.ty][p.tx-1][p.ky][p.kx+1]){
        inc_tx = -1 ; inc_kx = 1;
        if(is_out_of_area(p.ty,p.tx + inc_tx)){
          inc_tx = 0;
        }
        if(is_out_of_area(p.ky,p.kx + inc_kx)){
          inc_kx = 0;
        }
        if(inc_tx || inc_kx){
          q.set(p.tx + inc_tx,p.ty,p.kx + inc_kx,p.ky);
          q.d = p.d + 1;
          qa.push(q);
          D[q.ty][q.tx][q.ky][q.kx] = 0;
        }
      }
      if(D[p.ty][p.tx+1][p.ky][p.kx-1]){
        inc_tx = 1 ; inc_kx = -1;
        if(is_out_of_area(p.ty,p.tx + inc_tx)){
          inc_tx = 0;
        }
        if(is_out_of_area(p.ky,p.kx + inc_kx)){
          inc_kx = 0;
        }
        if(inc_tx || inc_kx){
          q.set(p.tx + inc_tx,p.ty,p.kx + inc_kx,p.ky);
          q.d = p.d + 1;
          qa.push(q);
          D[q.ty][q.tx][q.ky][q.kx] = 0;
        }
      }

    }
    while(!qa.empty()){
      qa.pop();
    } //キューの残りカスを消去
  }
  return 0;
}

C++: #include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
#define INF 1<<10

int xs[] = {0, 1, 0, -1}, ys[] = {1, 0, -1, 0};
int x, y;
int field[55][55];
short int  dp[55][55][55][55];

short int solve(int tx, int ty, int kx, int ky, int depth){
  if(depth > 3000)return INF;
  int ntx, nty, nkx, nky;
  if(dp[tx][ty][kx][ky] != -1){
    return dp[tx][ty][kx][ky];
  }
  dp[tx][ty][kx][ky] = INF;
  for(int i = 0;i < 4;i++){
    ntx = tx + xs[i];
    nty = ty + ys[i];
    nkx = kx - xs[i];
    nky = ky - ys[i];
    if(ntx < 0 || ntx >= x || nty < 0 || nty >= y || field[ntx][nty] == 1){
      ntx = tx;
      nty = ty;
    }
    if(nkx < 0 || nkx >= x || nky < 0 || nky >= y || field[nkx][nky] == 1){
      nkx = kx;
      nky = ky;
    }
    dp[tx][ty][kx][ky] = min(dp[tx][ty][kx][ky], (short int) (solve(ntx, nty, nkx, nky, depth + 1) + 1));
  }
  return dp[tx][ty][kx][ky];
}

int main(){
  int tx, ty, kx, ky;
  while(true){
    scanf("%d%d", &x, &y);
    memset(dp, -1, sizeof(dp));
    if(x == 0 && y == 0) return 0;
    scanf("%d%d", &tx, &ty);
    scanf("%d%d", &kx, &ky);
    for(int i = 0;i < y;i++){
      for(int j = 0;j < x;j++){
	scanf("%d", &field[j][i]);
	dp[j][i][j][i] = 0;
	dp[i][j][i][j] = 0;
      }
    }
    short int ans = solve(tx - 1, ty - 1, kx - 1, ky - 1, 0);
    if(ans >= 100)
      puts("NA");
    else
      printf("%d\n", ans);
  }
}

C++: #include <iostream>
using namespace std;
struct pos { int td,kd; };
int dm[50][50],tc[2500][2500],pn[2],g;
pos p[2][3000000];

int main() {
	int ax,ay,i,j,t,x,y,tx,ty,kx,ky,tx2,ty2,kx2,ky2,dx[4]={1,0,-1,0},dy[4]={0,-1,0,1};
	while(cin >> x >> y && x>0) {
		pn[0]=1; g=0;
		for (i=0;i<x*y;i++) for (j=0;j<x*y;j++) tc[i][j]=0;
		cin >> tx >> ty >> kx >> ky;
		ax=(ty-1)*x+tx-1; ay=(ky-1)*x+kx-1; tc[ax][ay]=1; p[g][0].td=ax; p[g][0].kd=ay;
		for (i=0;i<y;i++) for (j=0;j<x;j++) cin >> dm[i][j];
		for (t=1;t<101;t++) {
			pn[1-g]=0;
			for (i=0;i<pn[g];i++) {
				tx=p[g][i].td % x; ty=p[g][i].td/x;
				kx=p[g][i].kd % x; ky=p[g][i].kd/x;
				for (j=0;j<4;j++) {
					ax=tx+dx[j]; ay=ty+dy[j];
					if (ax>=0 && ax<x && ay>=0 && ay<y) if (dm[ay][ax]==0) { tx2=ax; ty2=ay;}
					ax=kx-dx[j]; ay=ky-dy[j];
					if (ax>=0 && ax<x && ay>=0 && ay<y) if (dm[ay][ax]==0) { kx2=ax; ky2=ay;}
					if (tx2==kx2 && ty2==ky2) break;
					ax=ty2*x+tx2; ay=ky2*x+kx2;
					if (tc[ax][ay]==0) { tc[ax][ay]=1; p[1-g][pn[1-g]].td=ax; p[1-g][pn[1-g]].kd=ay; pn[1-g]++;}
				}
				if (j<4) break;
			}
			if (j<4) break;
			g=1-g;
		}
		if (j<4 && t<101) cout << t << endl; else cout << "NA" << endl;
	} 
	return 0;
}