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;
struct l{
	int tx;
	int ty;
	int kx;
	int ky;
	int cnt;
};
queue<l> p;
int ps[50505050]={};
int main(){
	int x,y,tlx,tly,klx,kly,d[50][50],i,j,cl,tmx[4]={0,1,0,-1},tmy[4]={-1,0,1,0},kmx[4]={0,-1,0,1},kmy[4]={1,0,-1,0},k,z;
	l v;
	while(1){
		cin>>x>>y;
		if(x==0&&y==0)break;
		cin>>tlx>>tly;
		cin>>klx>>kly;
		for(i=0;i<y;i++){
			for(j=0;j<x;j++){
				cin>>d[i][j];
			}
		}
		v.tx=tlx-1;
		v.ty=tly-1;
		v.kx=klx-1;
		v.ky=kly-1;
		v.cnt=0;
		p.push(v);
		while(1){
			tlx=p.front().tx;
			tly=p.front().ty;
			klx=p.front().kx;
			kly=p.front().ky;
			cl=p.front().cnt;
			p.pop();
			if(tlx==klx&&tly==kly||cl>=100){
				while(!p.empty()){
					p.pop();
				}
				for(i=0;i<50505050;i++){
					ps[i]=0;
				}
				break;
			}
			if(ps[tlx*1000000+tly*10000+klx*100+kly]==1){
				if (!p.empty())
					continue;
				else
					break;
			}
			else{
				ps[tlx*1000000+tly*10000+klx*100+kly]=1;
			}
			for(i=0;i<4;i++){
				if(d[tly+tmy[i]][tlx+tmx[i]]==0&&(tlx+tmx[i])>=0&&(tlx+tmx[i])<x&&(tly+tmy[i])>=0&&(tly+tmy[i])<y){
					v.tx=tlx+tmx[i];
					v.ty=tly+tmy[i];
				}
				else{
					v.tx=tlx;
					v.ty=tly;
				}
				if(d[kly+kmy[i]][klx+kmx[i]]==0&&(klx+kmx[i])>=0&&(klx+kmx[i])<x&&(kly+kmy[i])>=0&&(kly+kmy[i])<y){
					v.kx=klx+kmx[i];
					v.ky=kly+kmy[i];
				}
				else{
					v.kx=klx;
					v.ky=kly;
				}
				v.cnt=cl+1;
				p.push(v);
			}
			
		}
		if(tlx==klx&&tly==kly&&cl!=0){
			cout<<cl<<endl;
		}
		else{
			cout<<"NA"<<endl;
		}
	}
????????????return 0;
}

C++: #include <bits/stdc++.h>

using namespace std;

struct People {
    int cnt;
    int tx, ty;
    int kx, ky;
};

int ans;
int X, Y;
int tx, ty;
int kx, ky;
int graph[50][50];
int check[50][50][50][50];
int vx[] = {0, 1, 0, -1};
int vy[] = {-1, 0, 1, 0};

int main() {

    while(cin >> X >> Y, X || Y) {

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

        for(int i = 0; i < Y; ++i) {
            for(int j = 0; j < X; ++j) {
                cin >> graph[i][j];
            }
        }

        queue<People> q;
        q.push((People){0, tx - 1, ty - 1, kx - 1, ky - 1});

        memset(check, 0, sizeof(check));

        ans = -1;

        while(!q.empty()) {

            People now = q.front(); q.pop();
            check[now.tx][now.ty][now.kx][now.ky] = 1;

            /*
            for(int i = 0; i < Y; ++i) {
                for(int j = 0; j < X; ++j) {
                    if(i == now.ty && j == now.tx) {
                        cout << "T";
                    } else if(i == now.ky && j == now.kx) {
                        cout << "K";
                    } else {
                        cout << graph[i][j];
                    }
                    cout << " ";
                }
                cout << endl;
            }
            cout << now.cnt << endl;
            cout << endl;
            */

            if(now.tx == now.kx && now.ty == now.ky) {
                if(now.cnt >= 100) {
                    break;
                }
                ans = now.cnt;
                break;
            }

            for(int i = 0; i < 4; ++i) {

                People next = now;
                next.cnt++;
                next.tx += vx[i];
                next.ty += vy[i];
                next.kx += vx[i] * -1;
                next.ky += vy[i] * -1;

                if( next.tx >= 0 && next.tx < X && next.ty >= 0 && next.ty < Y && !graph[next.ty][next.tx] &&
                    next.kx >= 0 && next.kx < X && next.ky >= 0 && next.ky < Y && !graph[next.ky][next.kx] &&
                    !check[next.tx][next.ty][next.kx][next.ky]) {

                    q.push(next);

                } else if(  next.tx >= 0 && next.tx < X && next.ty >= 0 && next.ty < Y && !graph[next.ty][next.tx] &&
                            !check[next.tx][next.ty][next.kx][next.ky]) {

                    next.kx = now.kx;
                    next.ky = now.ky;
                    q.push(next);

                } else if(  next.kx >= 0 && next.kx < X && next.ky >= 0 && next.ky < Y && !graph[next.ky][next.kx] &&
                            !check[next.tx][next.ty][next.kx][next.ky]) {

                    next.tx = now.tx;
                    next.ty = now.ty;
                    q.push(next);

                }

            }

        }

        if(ans == -1) {
            cout << "NA" << endl;
        } else {
            cout << ans << endl;
        }

    }

}