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<utility>
#include<queue>
using namespace std;
int dx[4] = { 1,0,-1,0 };
int dy[4] = { 0,1,0,-1 };
int main() {
	int W, H, tx, ty, kx, ky;
	bool d[52][52];
	bool memo[52][52][52][52];
	while (true) {
		cin >> W >> H;
		if (W == 0)break;
		for (int i = 0; i < 52; i++) {
			for (int j = 0; j < 52; j++) {
				for (int k = 0; k < 52; k++) {
					for (int l = 0; l < 52; l++) {
						memo[i][j][k][l] = false;
					}
				}
			}
		}
		for (int i = 0; i < 52; i++) {
			for (int j = 0; j < 52; j++) {
				d[i][j] = 1;
			}
		}
		cin >> tx >> ty >> kx >> ky;
		for (int i = 1; i < H + 1; i++) {
			for (int j = 1; j < W + 1; j++) {
				cin >> d[j][i];
			}
		}
		pair<pair<int, int>, pair<int, int> >num;
		num.first.first = tx;
		num.first.second = ty;
		num.second.first = kx;
		num.second.second = ky;
		queue<pair<pair<int, int>, pair<int, int> > > q;
		q.push(num);
		int qsize = q.size();
		int loopcount = 0;
		while (!q.empty()) {
			num = q.front();
			q.pop();
			if (qsize == 0) {
				qsize = q.size()+1;
				loopcount++;
				if (loopcount == 100) {
					cout << "NA" << endl;
					break;
				}
			}
			qsize--;
			memo[num.first.first][num.first.second][num.second.first][num.second.second] = true;
			memo[num.second.first][num.second.second][num.first.first][num.first.second] = true;
			if (num.first.first == num.second.first && num.first.second == num.second.second) {
				cout << loopcount << endl;
				break;
			}
			for (int i = 0; i < 4; i++) {
				pair<pair<int, int>, pair<int, int> >copy;
				copy = num;
				copy.first.first += dx[i];
				copy.first.second += dy[i];
				if (d[copy.first.first][copy.first.second]) {
					copy.first.first -= dx[i];
					copy.first.second -= dy[i];
				}
				copy.second.first -=dx[i];
				copy.second.second -= dy[i];
				if (d[copy.second.first][copy.second.second]) {
					copy.second.first += dx[i];
					copy.second.second += dy[i];
				}
				if (!memo[copy.first.first][copy.first.second][copy.second.first][copy.second.second]) {
					q.push(copy);
				}
			}
			if (q.empty()) {
				cout << "NA" << endl;
			}
		}
	}
	return 0;
}

C++: #include<iostream>
#include<queue>
#include<cstring>
using namespace std;
struct PP{
	int kx;
	int ky;
	int tx;
	int ty;
	int Z;
};
int w,h;
PP S;
bool A[53][53][53][53],D[53][53];
int main(){
	queue<PP> P;
	int d=0,i=0,j=0,l=-1;
	int tx[4]={ 1, 0,-1,0 };       
	int ty[4]={ 0, 1, 0,-1 };
	cin>>w>>h;
	while(w!=0||h!=0){
		memset(A,0,sizeof(A));
		for(i=0;i<=h+1;i++){
			for(j=0;j<=w+1;j++){
				D[i][j]=1;
			}
		}

		cin>>S.tx>>S.ty;
		cin>>S.kx>>S.ky;
		for(i=1;i<=h;i++){
			for(j=1;j<=w;j++){
				cin>>D[i][j];
			}
		}
		S.Z=0;
		P.push(S);
		if(S.tx==S.kx&&S.ty==S.ky){
			d=-1;
			cout<<S.Z<<endl;
		}
		while(d!=-1){
			l++;
			S=P.front();
			if(l==4){
				l=0;
				P.pop();
			//	if(P.empty()){
			//		cout<<"NA"<<endl;
			//		break;
			//	}
			}

			S.tx=S.tx+tx[l];
			S.ty=S.ty+ty[l];
			S.kx=S.kx+tx[l]*-1;
			S.ky=S.ky+ty[l]*-1;
			if(A[S.ty][S.tx][S.ky][S.kx]==1||(D[S.ty][S.tx]==1&&D[S.ky][S.kx]==1)){
				continue;
			}
			A[S.ty][S.tx][S.ky][S.kx]=1;

			if(D[S.ty][S.tx]==1){
				S.tx=S.tx-tx[l];
				S.ty=S.ty-ty[l];
			}
			if(D[S.ky][S.kx]==1){
				S.kx=S.kx-tx[l]*-1;
				S.ky=S.ky-ty[l]*-1;
			}
			//saka();
			S.Z++;
			P.push(S);
			if(S.tx==S.kx&&S.ty==S.ky){
				cout<<S.Z<<endl;
				break;
			}	
			if(S.Z==100){
				cout<<"NA"<<endl;
				break;
			}


		}
		while(!P.empty()){
			P.pop();
		}
		d=0;
		l=-1;
		cin>>w>>h;
	}	
	return 0;
}

C++: #include<stdio.h>
#include<queue>
using namespace std;
queue<int> tx, ty, kx, ky;
int d[50][50];
void move(void);
void clean(void);
int main(void)
{
	int x, y, X, Y,i,j;
	while (1) {
		for (i = 0; i < 50; i++) {
			for (j = 0; j < 50; j++) {
				d[i][j] = 1;
			}
		}
		scanf("%d %d", &X, &Y);   //????????????
		if (X == 0 && Y == 0) break;
		scanf("%d %d", &x, &y);   //????????????
		tx.push(x);  ty.push(y);
		scanf("%d %d", &x, &y);   //????????????
		kx.push(x);  ky.push(y);
		for (i = 1; i <= Y; i++) {
			for (j = 1; j <= X; j++) {
				scanf("%d", &d[i][j]);
			}
		}
		move();
		clean();
	}
	return 0;
}

void move()
{
	int cnt = 0,count=0,s=4;
	int m[4][4]={-1,1,0,0,      //taka y
				 0,0,-1,1,      //taka x
				 1,-1,0,0,      //kazu y
				 0,0,1,-1};     //kazu x
	while (1) {
		if (tx.back() == kx.back() && ty.back() == ky.back()) {
			printf("A%d\n", count);
			break;
		}
		if (d[ty.front() + m[0][cnt%4]][tx.front() + m[1][cnt%4]] == 0) {              //?????????
			tx.push(tx.front() + m[1][cnt%4]);
			ty.push(ty.front() + m[0][cnt%4]);
		}
		else if (d[ty.front() + m[0][cnt%4]][tx.front() + m[1][cnt%4]] == 1) {
			tx.push(tx.front());
			ty.push(ty.front());
		}
		if (d[ky.front() + m[2][cnt%4]][kx.front() + m[3][cnt%4]] == 0) {              //?????????
			kx.push(kx.front() + m[3][cnt%4]);
			ky.push(ky.front() + m[2][cnt%4]);
		}
		else if (d[ky.front() + m[2][cnt%4]][kx.front() + m[3][cnt%4]] == 1) {
			kx.push(kx.front());
			ky.push(ky.front());
		}

		cnt++;
		
		if(cnt == s){
			count++;
			s = s * s;
			cnt = 0;
			printf("\nQQQ\n");
		}
		//printf("%d ??????x.%d y.%d   ??????x.%d y.%d\n",cnt%4, tx.back(),ty.back(), kx.back(),ky.back());
		//printf("X %d %d\nY %d %d",kx.front(),m[3][cnt%4],ky.front(),m[2][cnt%4]);
		if (tx.back() == kx.back() && ty.back() == ky.back()) {
			printf("%d\n", count+1);
			break;
		}
	
		if(cnt % 4 == 0 && cnt !=0){
			tx.pop();  ty.pop();  kx.pop();  ky.pop();
		}
		if (count >= 100) {
			printf("NA\n");
			break;
		}
	}
}

void clean(void)
{
	while (!tx.empty()) {
		tx.pop();
	}
	while (!ty.empty()) {
		ty.pop();
	}
	while (!kx.empty()) {
		kx.pop();
	}
	while (!ky.empty()) {
		ky.pop();
	}
}