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 <bits/stdc++.h>
using namespace std;

int table[51][51];

bool memo[51][51][51][51];

int main() {

    while(1){

        int w,h;

        scanf(" %d %d",&w,&h);

        if(w==0&&h==0) break;

        int tx,ty,kx,ky;

        scanf(" %d %d %d %d",&tx,&ty,&kx,&ky);

        tx--;ty--;kx--;ky--;

        for(int i=0;i<51;i++){
            for(int j=0;j<51;j++){
                table[i][j] = 1;
                for(int k=0;k<51;k++){
                    for(int r=0;r<51;r++){
                        memo[i][j][k][r] = false;

                    }
                }
            }
        }

        for(int i=0;i<h;i++){
            for(int j=0;j<w;j++){
                scanf(" %d",&table[i][j]);
            }
        }

        //memset(memo,false,sizeof(memo));

        queue<vector<int> > q;

        vector<int> v(5);

        v[0] = tx; v[1] = ty; v[2] = kx; v[3] = ky; v[4] = 0;

        q.push(v);

        bool check = false;

        while(!q.empty()){

            v = q.front(); q.pop();

            if(v[4] >= 100){
                break;
            }

            if(memo[v[0]][v[1]][v[2]][v[3]]){
                continue;
            }

            if(v[0] >= w || v[1] >= h || v[2] >= w || v[3] >= h || v[0] < 0 || v[1] < 0 || v[2] < 0 || v[3] < 0 || table[v[0]][v[1]] == 1 || table[v[2]][v[3]] == 1){
                continue;
            }

            if(v[0] == v[2] && v[1] == v[3]){
                check = true;
                printf("%d\n",v[4]);
                break;
            }

            memo[v[0]][v[1]][v[2]][v[3]] = true;

            v[4]++;

            vector<int> before(5);

            for(int i=0;i<5;i++){
                before[i] = v[i];
            }

            v[0]--; v[2]++;

            q.push(v);

            for(int i=0;i<5;i++){
                v[i] = before[i];
            }

            v[0]++; v[2]--;

            q.push(v);

            for(int i=0;i<5;i++){
                v[i] = before[i];
            }

            v[1]++; v[3]--;

            q.push(v);

            for(int i=0;i<5;i++){
                v[i] = before[i];
            }

            v[1]--; v[3]++;

            q.push(v);

            /*if(v[0] >= w || v[1] >= h || v[2] >= w || v[3] >= h || v[0] < 0 || v[1] < 0 || v[2] < 0 || v[3] < 0 || table[v[0]][v[1]] == 1 || table[v[2]][v[3]] == 1){

            }else {
                q.push(v);
            }*/



        }

        if(!check){
            printf("NA\n");
        }



    }

    return 0;
}

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

bool went[50 + 10][50 + 10][50 + 10][50 + 10] = { 0 };

int map[50 + 10][50 + 10] = { 0 };

int gx[] = { 1,0,-1,0,-1,0,1,0 };
int gy[] = { 0,1,0,-1,0,-1,0,1 };

struct ST
{
	int tx, ty;
	int kx, ky;
	int tim=0;
};

bool ChekNow(ST);


ST GoMap(ST, int);


int main()
{
	ST now,tmp;

	queue <ST> nx;


	int w, h;
	int tsx, tsy;
	int ksx, ksy;

	bool flg;
	int i, j;

	while (cin >> w >> h, w != 0 && h != 0)
	{
		flg = true;

		cin >> tsx >> tsy;
		cin >> ksx >> ksy;
		
		for (i = 1; i <= h; i++)
		{
			map[i][0] = map[i][w + 1] = 1;

			for (j = 1; j <= w; j++)
			{
				cin >> map[i][j];
			}
		}

		for (i = 0; i <= w + 1; i++)
		{
			map[0][i] = 1;
			map[h + 1][i] = 1;
		}


		now.tx = tsx;
		now.ty = tsy;
		now.kx = ksx;
		now.ky = ksy;
		now.tim = 0;

		nx.push(now);

		while (!nx.empty() && tmp.tim<100)
		{
			now = nx.front();
			nx.pop();

			if (ChekNow(now))
			{
				continue;
			}
			went[now.tx][now.ty][now.kx][now.ky] = true;

			if (now.tx == now.kx && now.ty == now.ky)
			{
				cout << now.tim << endl;

				flg = false;

				break;
			}

			for (i = 0; i < 4; i++)
			{
				tmp=GoMap(now, i);

				if (!ChekNow(tmp))
				{
					tmp.tim++;
					nx.push(tmp);
				}
			}
		}

		if (flg)
		{
			cout << "NA\n";
		}

		while (!nx.empty())
		{
			nx.pop();
		}
	}
	return 0;
}


bool ChekNow(ST ex)
{
	return went[ex.tx][ex.ty][ex.kx][ex.ky];
}


ST GoMap(ST ex, int i)
{
	if (map[ex.ty + gy[i]][ex.tx + gx[i]] == 0)
	{
		ex.ty += gy[i];
		ex.tx += gx[i];
	}
	if (map[ex.ky + gy[i + 4]][ex.kx + gx[i + 4]] == 0)
	{
		ex.ky += gy[i + 4];
		ex.kx += gx[i + 4];
	}

	return ex;
}