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 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<queue>
#include<stdio.h>

using namespace std;

class T{
	public:
	int x1,x2,y1,y2,count;
	T(int x1,int y1,int x2,int y2,int count):x1(x1),y1(y1),x2(x2),y2(y2),count(count){}
};

char check[55][55][55][55];
int board[55][55];

int main(){
	while(1){
		for(int i=0;i<55;i++){
			for(int j=0;j<55;j++){
				board[i][j]=0;
				for(int k=0;k<55;k++){
					for(int p=0;p<55;p++){
						check[i][j][k][p]=0;
					}
				}
			}
		}
		
		int w,h;
		int sx1,sx2,sy1,sy2;
		
		scanf("%d%d",&w,&h);
		if(w==0 && h==0)break;
		
		scanf("%d%d%d%d",&sx1,&sy1,&sx2,&sy2);
		
		for(int i=0;i<h;i++){
			for(int j=0;j<w;j++){
				scanf("%d",&board[i][j]);
			}
		}
		
		
		queue<T> que;
		que.push(T(sx1,sy1,sx2,sy2,0));
		
		while(1){
			if(que.empty())break;
			
			T u = que.front();
			que.pop();
			
			if(check[u.x1][u.y1][u.x2][u.y2]==1)continue;
			check[u.x1][u.y1][u.x2][u.y2]=1;
			
			if(u.count>=100)break;
			if(u.x1 == u.x2 && u.y1 == u.y2){
				printf("%d\n",u.count);
				goto A;
			}
			
			int dx[4] = {0,1,0,-1};
			int dy[4] = {1,0,-1,0};
			for(int i=0;i<4;i++){
				int nx1 = u.x1 + dx[i];
				int ny1 = u.y1 + dy[i];
				
				int nx2 = u.x2 - dx[i];
				int ny2 = u.y2 - dy[i];
				
				if(nx1<0 || ny1<0 || nx1>=w || ny1>=h || board[ny1][nx1]==1){
					nx1=u.x1;
					ny1=u.y1;
				}
				if(nx2<0 || ny2<0 || nx2>=w || ny2>=h || board[ny2][nx2]==1){
					nx2=u.x2;
					ny2=u.y2;
				}
				que.push(T(nx1,ny1,nx2,ny2,u.count+1));
			}
		}
		
		printf("NA\n");
		A:;
	}
}

C++: #include <iostream>
#include <queue>
using namespace std;

const int INF = 1000000;
int H,W;
class Point{
public:
  int tx;
  int ty;
  int kx;
  int ky;
  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){
  return x < 1 || x > W || y < 1 || H > H;
}
int main(){
  char F[52][52];
  int D[52][52];
  
  int tx,ty,kx,ky;
  while(1){
    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++){
        D[y][x] = INF;
        int a;
        cin >> a;
        F[y][x] = a;
      }
    }
    
    queue<Point> qa;
    Point p;
    p.set(tx,ty,kx,ky);
    qa.push(p);
    D[p.ty][p.tx] = 0;
    while(!qa.empty()){
      p = qa.front();
      qa.pop();
      if(D[p.ty][p.tx] >= 100){
        cout << "NA" << endl;
        break;
      }
      if(p.tx == p.kx && p.ty == p.ky){
        cout << D[p.ty][p.tx] << endl;
        return 0;
      }
      
      if(D[p.ty-1][p.tx] == INF && D[p.ky+1][p.kx] == INF){
        if(is_out_of_area(p.ty-1,p.tx) == 0 || is_out_of_area(p.ky+1,p.kx) == 0){
          if(F[p.ty-1][p.tx] == 0 || F[p.ky+1][p.kx] == 0){
            Point q;
            q.set(p.tx,p.ty-1,p.kx,p.ky+1);
            qa.push(q);
            D[q.ty][q.tx] = D[p.ty][p.tx] + 1;
          }
        }
      }
      if(D[p.ty+1][p.tx] == INF && D[p.ky-1][p.kx] == INF){
        if(is_out_of_area(p.ty-1,p.tx) == 0 || is_out_of_area(p.ky+1,p.kx) == 0){
          if(F[p.ty+1][p.tx] == 0 || F[p.ky-1][p.kx] == 0){
            Point q;
            q.set(p.tx,p.ty+1,p.kx,p.ky-1);
            qa.push(q);
            D[q.ty][q.tx] = D[p.ty][p.tx] + 1;
          }
        }
      }
      if(D[p.ty][p.tx-1] == INF && D[p.ky][p.kx+1] == INF){
        if(is_out_of_area(p.ty,p.tx) == 0 || is_out_of_area(p.ky,p.kx) == 0){
          if(F[p.ty][p.tx-1] == 0 || F[p.ky][p.kx+1] == 0){
            Point q;
            q.set(p.tx-1,p.ty,p.kx+1,p.ky);
            qa.push(q);
            D[q.ty][q.tx] = D[p.ty][p.tx] + 1;
          }
        }
      }
      if(D[p.ty][p.tx+1] == INF && D[p.ky][p.kx-1] == INF){
        if(is_out_of_area(p.ty,p.tx+1) == 0 || is_out_of_area(p.ky,p.kx-1) == 0){
          if(F[p.ty][p.tx+1] == 0 || F[p.ky][p.kx-1] == 0){
            Point q;
            q.set(p.tx+1,p.ty,p.kx-1,p.ky);
            qa.push(q);
            D[q.ty][q.tx] = D[p.ty][p.tx] + 1;
          }
        }
      }
      
    }
    cout << "NA" << endl;
  }
  return 0;
}