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 <queue>
#include <vector>
#include <iostream>

#define INF (1 << 25)

using namespace std;

vector<vector<vector<vector<int> > > > dp;

vector<vector<int> > M;

int H, W, sx1, sy1, sx2, sy2;

const int dx[4] = { 0, 1, 0, -1 };
const int dy[4] = { 1, 0, -1, 0 };

int bfs()
{
	dp = vector<vector<vector<vector<int> > > >(H, vector<vector<vector<int> > >(W, vector<vector<int> >(H, vector<int>(W, INF)))); dp[sy1][sx1][sy2][sx2] = 0;

	queue<pair<pair<pair<int, int>, pair<int, int> >, int> > que; que.push(make_pair(make_pair(make_pair(sx1, sy1), make_pair(sx2, sy2)), 0));

 	while (!que.empty())
	{
		int x1 = que.front().first.first.first;
		int y1 = que.front().first.first.second;
		int x2 = que.front().first.second.first;
		int y2 = que.front().first.second.second;

		int turn = que.front().second;

		que.pop();

		for (int dir = 0; dir < 4; dir++)
		{
			int tx1 = x1 + dx[dir]; if (tx1 < 0 || tx1 >= W) { tx1 -= dx[dir]; }
			int ty1 = y1 + dy[dir]; if (ty1 < 0 || ty1 >= H) { ty1 -= dy[dir]; }
			int tx2 = x2 - dx[dir]; if (tx2 < 0 || tx2 >= W) { tx2 += dx[dir]; }
			int ty2 = y2 - dy[dir]; if (ty2 < 0 || ty2 >= H) { ty2 += dy[dir]; }

			if (M[ty1][tx1] == 1) { tx1 -= dx[dir]; ty1 -= dy[dir]; }
			if (M[ty2][tx2] == 1) { tx2 += dx[dir]; ty2 += dy[dir]; }

			if (tx1 == tx2 && ty1 == ty2) { return turn + 1; }

			if (dp[ty1][tx1][ty2][tx2] == INF)
			{
				dp[ty1][tx1][ty2][tx2] = turn + 1;

				que.push(make_pair(make_pair(make_pair(tx1, ty1), make_pair(tx2, ty2)), turn + 1));
			}
		}
	}

	return -1;
}

int main()
{
	while (true)
	{
		cin >> W >> H;

		if (H == 0 && W == 0) { break; }

		M = vector<vector<int> >(H, vector<int>(W));

		cin >> sx1 >> sy1 >> sx2 >> sy2;

		sx1--; sy1--; sx2--; sy2--;

		for (int i = 0; i < H; i++)
		{
			for (int j = 0; j < W; j++)
			{
				cin >> M[i][j];
			}
		}

		int Ans = bfs();

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

	return 0;
}

C++: #include<cstdio>
#include<iostream>
#include<vector>
#include<algorithm>
#include<map>
#include<set>
#include<queue>
#include<string>

using namespace std;

#define rep(i,n) for(int i=0;i<int(n);i++)
#define reps(i,n) for(int i=1;i<=int(n);i++)
#define sint(i) scanf("%d",&i);
#define sintt(i,j) scanf("%d%d",&i,&j);
#define sinttt(i,j,k) scanf("%d%d%d",&i,&j,&k);
#define sintttt(i,j,k,m) scanf("%d%d%d%d",&i,&j,&k,&m);

#define INF 1010000000
int dx[]={1,0,-1,0};
int dy[]={0,1,0,-1};

class S{
	public:
	int a,b,c,d;
	int n;
	S(int p,int n,int t,int k,int i):a(p),b(n),c(t),d(k),n(i){}
	
};

char visit[51][51][51][51];

int main(){
	while(1){
		int n,m;
		sintt(n,m);
		if(n==0)break;
		int a,b,c,d;
		sintttt(a,b,c,d);
		
		int masu[51][51];
		
		rep(i,51)rep(j,51)masu[j][i]=0;
		reps(i,m){
			reps(j,n){
				sint(masu[j][i]);
			}
		}
		
		queue<S> que;
		que.push(S(a,b,c,d,0));
		rep(i,51)rep(j,51)rep(k,51)rep(p,51)visit[i][j][k][p]=0;
		int ans=0;
		while(1){
			if(que.empty()==1){
				break;
			}
			
			
			S u=que.front();
			que.pop();
			
			//printf("%d %d  %d %d  %d\n",u.a,u.b,u.c,u.d,u.n);
			
			if(visit[u.a][u.b][u.c][u.d]==1){
				continue;
			}
			visit[u.a][u.b][u.c][u.d]=1;
			
			if(u.a==u.c && u.b==u.d){
				ans=u.n;
				break;
			}
			
			rep(i,4){
				int dx1=u.a+dx[i];
				int dy1=u.b+dy[i];
				
				int dx2=u.c+dx[i]*-1;
				int dy2=u.d+dy[i]*-1;
				
				//printf("push %d %d %d %d\n",dx1,dy1,dx2,dy2);
				
				if(dx1<=0 || dy1<=0 || dx1>n ||dy1>m|| masu[dx1][dy1]==1){
					dx1-=dx[i];
					dy1-=dy[i];
				}
				if(dx2<=0 || dy2<=0 || dx2>n ||dy2>m|| masu[dx2][dy2]==1){
					dx2-=dx[i]*-1;
					dy2-=dy[i]*-1;
				}
				
				//printf("push %d %d %d %d\n",dx1,dy1,dx2,dy2);
				que.push(S(dx1,dy1,dx2,dy2,u.n+1));
			}
		}
		if(ans==0){
			puts("NA");
		}else{
			printf("%d\n",ans);
		}
	}
}

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;
}