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 (pq PQStatus) Len() int {
	return len(pq)
}
func (pq PQStatus) Less(i, j int) bool {
	if pq[i].Turn == pq[j].Turn {
		return pq[i].Person.Distance() < pq[j].Person.Distance()
	}
	return pq[i].Turn < pq[j].Turn
}

func (pq PQStatus) Swap(i, j int) {
	pq[i], pq[j] = pq[j], pq[i]
}

func (pq *PQStatus) Push(x interface{}) {
	item := x.(*Status)
	*pq = append(*pq, item)
}

func (pq *PQStatus) Pop() interface{} {
	old := *pq
	n := len(old)
	item := old[n-1]
	*pq = old[0 : n-1]
	return item
}

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)
	//heap.Init(&pq)
	//heap.Push(&pq, start)
	//pq.Push(start)
	pq = append(pq, start)
	dx := []int64{0, 1, 0, -1}
	dy := []int64{1, 0, -1, 0}
	memo := make(map[PersonPosition]int64, 0)
	ans := int64(101)
	for pq.Len() > 0 {
		//now := heap.Pop(&pq).(*Status)
		//now := pq.Pop().(*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 += 1
			if next.Turn < 100 {
				//heap.Push(&pq, next)
				//pq.Push(next)
				pq = append(pq, next)
			}
		}
	}
	if ans == 101 {
		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>
#define rep2(x,from,to) for(int x=(from);(x)<(to);(x)++)
#define rep(x,to) rep2(x,0,to)
using namespace std;
bool mem[52][52][52][52] = {{{{}}}};
struct S{
	int a,b,c,d,t;
};
int dx[4] = {-1,0,1,0};
int dy[4] = {0,1,0,-1};
int main(){
	int x, y, tx, ty, kx, ky, k;
	while(cin >> x >> y, (x || y)) {
		int b[52][52] = {};
		cin >> tx >> ty >> kx >> ky;
		rep(i,y) {
			rep(j,x) {
				cin >> k;
				b[i+1][j+1] = 1-k;
			}
		}
		queue<S> q;
		S s = {tx,ty,kx,ky,0};
		q.push(s);
		while(!q.empty()) {
			S s = q.front();
			if(s.a==s.c&&s.b==s.d) break;
			if(q.front().t >= 100) break;
			q.pop();
			if(mem[s.a][s.b][s.c][s.d]++) continue;
			rep(i,4) {
				int na = s.a+dx[i], nb = s.b+dy[i], nc = s.c+dx[(i+2)%4], nd = s.d+dy[(i+2)%4];
				if(!b[nb][na]&&!b[nd][nc]) continue;
				if(!b[nb][na]) na = s.a, nb = s.b;
				if(!b[nd][nc]) nc = s.c, nd = s.d;
				S ns = {na, nb, nc, nd, s.t+1};
				q.push(ns);
			}
		}
		if(q.empty()) cout << "NA" << endl;
		else if(q.front().t >= 100) cout << "NA" << endl;
		else cout << q.front().t << endl;
	}
}

C++: #include<stdio.h>
#include<algorithm>
#include<queue>
using namespace std;
int m[50][50];
int dx[]={1,-1,0,0};
int dy[]={0,0,1,-1};
int bfs[50][50][50][50];
struct wolf{
	int a,b,c,d;
	wolf(int A,int B,int C,int D){
		a=A;
		b=B;
		c=C;
		d=D;
	}
};
int main(){
	int a,b;
	while(scanf("%d%d",&a,&b),a+b){
		int r1,r2,c1,c2;
		scanf("%d%d%d%d",&r1,&c1,&r2,&c2);
		for(int i=0;i<b;i++)
			for(int j=0;j<a;j++)
				scanf("%d",&m[i][j]);
		int inf=999999999;
		for(int i=0;i<b;i++)
			for(int j=0;j<a;j++)
				for(int k=0;k<b;k++)
					for(int l=0;l<a;l++)
						bfs[i][j][k][l]=inf;
		r1--;c1--;r2--;c2--;
		bfs[r1][c1][r2][c2]=0;
		queue<wolf> Q;
		Q.push(wolf(r1,c1,r2,c2));
		while(Q.size()){
			wolf at=Q.front();
			Q.pop();
		//	if(bfs[at.a][at.b][at.c][at.d]==99)continue;
			for(int i=0;i<4;i++){
				int s1=at.a+dx[i];
				int t1=at.b+dy[i];
				int s2=at.c-dx[i];
				int t2=at.d-dy[i];
				if(s1<0||s1>=b||m[s1][t1])s1-=dx[i];
				if(t1<0||t1>=a||m[s1][t1])t1-=dy[i];
				if(s2<0||s2>=b||m[s2][t2])s2+=dx[i];
				if(t2<0||t2>=a||m[s2][t2])t2+=dy[i];
				if(bfs[s1][t1][s2][t2]==inf){
					bfs[s1][t1][s2][t2]=bfs[at.a][at.b][at.c][at.d]+1;
					Q.push(wolf(s1,t1,s2,t2));
				}
			}
		}
		int ret=inf;
		for(int i=0;i<b;i++)for(int j=0;j<a;j++)ret=min(ret,bfs[i][j][i][j]);if(ret>=100)printf("NA\n");else printf("%d\n",ret);
	}
}

C++: #include<stdio.h>

#include<queue>
#include<iostream>
#include<string.h>
using namespace std;
struct PP{
	int kx;
	int ky;
	int tx;
	int ty;
	int Z;
};
int A[52][52][52][52];
int main(){
	PP S;
	queue<PP> P;
	int  w,h;
	int d=0,i=0,j=0,l=-1,D[54][54];
	int tx[4]={ 1, 0,-1,0 };       
	int kx[4]={-1, 0, 1,0 };
	int ty[4]={ 0, 1, 0,-1 };
	int ky[4]={ 0, -1, 0,1};
	scanf("%d %d",&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;
		}
	}

	scanf("%d %d",&S.tx,&S.ty);
	scanf("%d %d",&S.kx,&S.ky);
	A[S.tx+1][S.ty+1][S.kx+1][S.ky+1]=1;
	for(i=1;i<=h;i++){
		for(j=1;j<=w;j++){
		scanf("%d",&D[i][j]);
		}
	}
	S.Z=0;
	P.push(S);
		if(S.tx==S.kx&&S.ty==S.ky){
			d=-1;
			printf("%d\n",S.Z);
		}
	while(d!=-1){
		l++;
		if(l==4){
		l=0;
		S=P.front();
		P.pop();
		if(P.empty()){
			printf("NA\n");
		break;
		}
		}
		S=P.front();
		
		S.tx=S.tx+tx[l];
		S.ty=S.ty+ty[l];
		S.kx=S.kx+kx[l];
		S.ky=S.ky+ky[l];
		if(A[S.tx+1][S.ty+1][S.kx+1][S.ky+1]==1){
			continue;
		}
		A[S.tx+1][S.ty+1][S.kx+1][S.ky+1]=1;

		if(D[S.ty+1][S.tx+1]==1){
		S.tx=S.tx-tx[l];
		S.ty=S.ty-ty[l];
		}
		if(D[S.ky+1][S.kx+1]==1){
		S.kx=S.kx-kx[l];
		S.ky=S.ky-ky[l];
		}
		S.Z++;
		P.push(S);
		if(S.tx==S.kx&&S.ty==S.ky){
			printf("%d\n",S.Z);
			break;
		}	
		if(S.Z==100){
			printf("NA\n");
		break;
		}
	}
	while(!P.empty()){
	P.pop();
	}
	l=-1;
	scanf("%d %d",&w,&h);
	}	
	return 0;
}