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)
	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)
		if now.Person.Distance() == 0 && ans > now.Turn {
			ans = now.Turn
		}
		if v, ok := memo[now.Person]; ok && v <= now.Turn {
			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)
			}
		}
	}
	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>
#define M 53
#include<queue>
#include<cstring>
using namespace std;
struct P{
	int ax,ay,bx,by,cost;
	P(){}
	P(int h,int j,int k,int l,int co):
	ax(h),ay(j),bx(k),by(l),cost(co){}
};
int main(){
	bool s[M][M],d[M][M][M][M],u;
	int w,h,tx,ty,kx,ky,dx[]={1,-1,0,0},dy[]={0,0,-1,1};
	while(cin>>w>>h,w||h){
		cin>>tx>>ty;tx--;ty--;
		cin>>kx>>ky;kx--;ky--;
		for(int i=0;i<h;i++)
		for(int j=0;j<w;j++)
		cin>>s[i][j];
		queue<P> que;
		memset(d,sizeof(d),0);
		d[tx][ty][kx][ky]=1;
		que.push(P(tx,ty,kx,ky,0));
		u=true;
		while(!que.empty()){
			P p=que.front();
			que.pop();
			if(p.cost==100)
			break;
			if(p.ax==p.bx&&p.ay==p.by){
				cout<<p.cost<<endl;
				u=false;
				break;
			}
			int ntx,nty,nkx,nky;
			for(int i=0;i<4;i++){
				ntx=p.ax+dx[i];
				nty=p.ay+dy[i];
				nkx=p.bx-dx[i];
				nky=p.by-dy[i];
				if(!(ntx>=0&&ntx<w&&nty>=0&&nty<h)||s[nty][ntx]==1){
					ntx=p.ax;nty=p.ay;
				}
				if(!(nkx>=0&&nkx<w&&nky>=0&&nky<h)||s[nky][nkx]==1){
					nkx=p.bx;nky=p.by;
				}
				if(d[ntx][nty][nkx][nky]!=1)
				que.push(P(ntx,nty,nkx,nky,p.cost+1));
				d[ntx][nty][nkx][nky]=1;
			}
		}
		if(u)
		cout<<"NA"<<endl;
	}
	return 0;
}

C++: #include <iostream>
#include <queue>
#include <stack>
#include <vector>
#include <stdio.h>
#include <algorithm>
#include <string.h>
#include <string>
#include <cmath>
#include <complex>
#include <map>
using namespace std;

#define rep(i,n) for(int i=0;i<int(n);++i)
#define ALL(v) (v).begin(),(v).end()
#define PB push_back
#define EPS 1e-8
#define F first
#define S second

static const double PI=6*asin(0.5);
typedef long long ll;
typedef complex<double> CP;
typedef pair<int,int> P;
static const int INF=1<<24;

int a[60][60][60][60]={0};
int m[60][60];
int b[5][3];
int c[5][3];
int main(){
	b[0][0]=1; b[0][1]=0;
	b[1][0]=0; b[1][1]=-1;
	b[2][0]=-1; b[2][1]=0;
	b[3][0]=0; b[3][1]=1;
	c[0][0]=-1; c[0][1]=0;
	c[1][0]=0; c[1][1]=1;
	c[2][0]=1; c[2][1]=0;
	c[3][0]=0; c[3][1]=-1;
	queue<pair<P,P> > qu;
	pair<P,P> tmp;
	int X,Y;
	while(cin>>X>>Y,X){
		//cout<<X<<" "<<Y<<endl;
		//3 4 5 2
		//3 3 5 3
		//4 3 4 3
		memset(a,0,sizeof(a));
		rep(i,60){
			rep(j,60){
				m[i][j]=1;
			}
		}
		
		while(!qu.empty()) qu.pop();
		P ta,ka;
		//cout<<"hoge"<<endl;
		cin>>ta.F>>ta.S>>ka.F>>ka.S;
		rep(i,Y){
			rep(j,X){
				cin>>m[j+1][i+1];
			}
		}
		/*
		rep(i,Y+2){
			rep(j,X+2){
				cout<<m[j][i]<<" ";
			}
			cout<<endl;
		}
		*/
		a[ta.F][ta.S][ka.F][ka.S]=1;
		tmp.F=ta;
		tmp.S=ka;
		qu.push(tmp);
		bool f=true;
		int tt;
		rep(i,100){
			tt=qu.size();
			rep(h,tt){
				P tta=qu.front().F,kka=qu.front().S;
				//cout<<"tta "<<tta.F<<" "<<tta.S<<"  kka "<<kka.F<<" "<<kka.S<<endl;
				qu.pop();
				if(tta.F==kka.F&&tta.S==kka.S){
					cout<<i<<endl;
					f=false;
					break;
				}
				rep(j,4){
					if(m[tta.F+b[j][0]][tta.S+b[j][1]]==1){
						tmp.F=tta;
					}
					else{
						tmp.F.F=tta.F+b[j][0];
						tmp.F.S=tta.S+b[j][1];
					}
					
					if(m[kka.F+c[j][0]][kka.S+c[j][1]]==1){
						tmp.S=kka;
					}
					else{
						tmp.S.F=kka.F+c[j][0];
						tmp.S.S=kka.S+c[j][1];
					}
					if(a[tmp.F.F][tmp.F.S][tmp.S.F][tmp.S.S]==1){
						continue;
					}
					else{
						qu.push(tmp);
						//cout<<"j="<< j<<" "<<tmp.F.F<<" "<<tmp.F.S<<" "<<tmp.S.F<<" "<<tmp.S.S<<endl;
						a[tmp.F.F][tmp.F.S][tmp.S.F][tmp.S.S]=1;
					}
				}
				//cout<<endl;
			}
			if(!f) break;
		}
		if(f) cout<<"NA\n";
	}
	return 0;
}