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 <iostream>
#include <queue>
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;
  }
};

int 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;
    for(int y=0;y<=H+1;y++){
      for(int x=0;x<=W+1;x++){
        F[y][x] = 1;
      }
    }
    for(int y=1;y<=H;y++){
      for(int x=1;x<=W;x++){
        cin >> F[y][x];
      }
    }
    for(int y=1;y<=H;y++){
      for(int x=1;x<=W;x++){
        for(int i=1;i<=H;i++){
          for(int j=1;j<=W;j++){
            D[y][x][i][j] = 1; //1:未探索 , 0:探索済み
          }
        }
      }
    }
    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 <stdio.h>
#include <set>
#include <list>

using namespace std;

typedef struct {
	int tx, ty;
	int kx, ky;
	int depth;
} DATA;

set<unsigned int> hash;
list<DATA> width_sarch;
int map[100 + 2][100 + 2];

unsigned int calc_hash(DATA &data)
{
	return (data.tx | (data.ty << 8) | (data.kx << 16) | (data.ky << 24));
}

int main(void)
{
	int width, hight;
	int tx, ty, kx, ky;
	DATA add;
	
	while (1){
		hash.clear();
		width_sarch.clear();
		
		scanf("%d%d", &width, &hight);
		if (width == 0 && hight == 0){
			break;
		}
		scanf("%d%d%d%d", &add.tx, &add.ty, &add.kx, &add.ky);
		
		add.depth = 0;
		hash.insert(calc_hash(add));
		width_sarch.push_back(add);
		
		for (int i = 0; i <= hight + 1; i++){
			for (int j = 0; j <= width + 1; j++){
				map[i][j] = 1;
			}
		}
		
		for (int y = 1; y <= hight; y++){
			for (int x = 1; x <= width; x++){
				scanf("%d", &map[x][y]);
			}
		}
		
		while (!width_sarch.empty() && width_sarch.front().depth < 100){
			if (width_sarch.front().tx == width_sarch.front().kx && width_sarch.front().ty == width_sarch.front().ky){
				break;
			}
			
			
			tx = width_sarch.front().tx;
			ty = width_sarch.front().ty;
			kx = width_sarch.front().kx;
			ky = width_sarch.front().ky;
			add.depth = width_sarch.front().depth + 1;
			
			add.ty = ty;
			add.ky = ky;
			
			add.tx = map[tx + 1][ty] == 0 ? tx + 1 : tx;
			add.kx = map[kx - 1][ky] == 0 ? kx - 1 : kx;
			if (hash.find(calc_hash(add)) == hash.end()){
				hash.insert(calc_hash(add));
				width_sarch.push_back(add);
			}
			add.tx = map[tx - 1][ty] == 0 ? tx - 1 : tx;
			add.kx = map[kx + 1][ky] == 0 ? kx + 1 : kx;
			if (hash.find(calc_hash(add)) == hash.end()){
				hash.insert(calc_hash(add));
				width_sarch.push_back(add);
			}
			
			add.tx = tx;
			add.kx = kx;
			
			add.ty = map[tx][ty + 1] == 0 ? ty + 1 : ty;
			add.ky = map[kx][ky - 1] == 0 ? ky - 1 : ky;
			if (hash.find(calc_hash(add)) == hash.end()){
				hash.insert(calc_hash(add));
				width_sarch.push_back(add);
			}
			add.ty = map[tx][ty - 1] == 0 ? ty - 1 : ty;
			add.ky = map[kx][ky + 1] == 0 ? ky + 1 : ky;
			if (hash.find(calc_hash(add)) == hash.end()){
				hash.insert(calc_hash(add));
				width_sarch.push_back(add);
			}
			
			
			width_sarch.pop_front();
		}
		
		if (width_sarch.empty() || width_sarch.front().depth >= 100){
			puts("NA");
		}
		else {
			printf("%d\n", width_sarch.front().depth);
		}
	}
	
	return (0);
}