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 := &Status{}
		*now = *pq[0]
		pq = pq[1:]
		if ans <= now.Turn {
			continue
		}
		if _, ok := memo[now.Person]; ok {
			continue
		}
		memo[now.Person] = now.Turn

		if now.Person.Distance() == 0 && ans > now.Turn {
			ans = 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 <queue>
#include <cstring>
using namespace std;

int field[50][50];
bool visit[50][50][50][50];

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

int main()
{
	int w,h,ax,ay,bx,by;

	while(cin >> w >> h, w||h)
	{
		cin >> ax >> ay;
		cin >> bx >> by;

		for(int y=0; y<h; y++)
		for(int x=0; x<w; x++)
		{
			cin >> field[y][x];
		}
		memset(visit,0,sizeof(visit));

		int cnt=0;
		bool flag=false;
		queue<int> q;
		q.push(ax-1);
		q.push(ay-1);
		q.push(bx-1);
		q.push(by-1);
		while(!q.empty())
		{
			int len=q.size()/4;
			for(int l=0; l<len; l++)
			{
				ax=q.front(); q.pop();
				ay=q.front(); q.pop();
				bx=q.front(); q.pop();
				by=q.front(); q.pop();

				if(ax==bx && ay==by)
				{
					flag=true;
					break;
				}
				visit[ax][ay][bx][by] = 1;

				for(int d=0; d<4; d++)
				{
					int px = ax+dx[d];
					int py = ay+dy[d];
					int qx = bx-dx[d];
					int qy = by-dy[d];

					if(px<0 || w<=px || py<0 || h<=py) { px=ax; py=ay; }
					if(qx<0 || w<=qx || qy<0 || h<=qy) { qx=bx; qy=by; }
					if(field[py][px]) { px=ax; py=ay; }
					if(field[qy][qx]) { qx=bx; qy=by; }

					if(!visit[px][py][qx][qy])
					{
						q.push(px);
						q.push(py);
						q.push(qx);
						q.push(qy);
					}
				}
			}

			if(flag) break;

			cnt++;
		}

		if(flag)
		{
			cout << cnt << endl;
		}
		else
		{
			cout << "NA" << endl;
		}
	}

}

C++: #include<stdio.h>
#include<iostream>
#include<queue>
using namespace std;
struct oza{
	int x;
	int y;
};
int A[52][52][52][52];
int main(){
	oza k;
	oza t;
	queue<oza> ka;
	queue<oza> ta;
	queue<int> Z;
	int  w,h,b;
	int d=0,c=0,i=0,j=0,l=-1,D[52][52];
	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",&t.x,&t.y);
	scanf("%d %d",&k.x,&k.y);
	for(i=1;i<=h;i++){
		for(j=1;j<=w;j++){
		scanf("%d",&D[i][j]);
		}
	}
	ta.push(t);
	ka.push(k);
	Z.push(c);
		if(t.x==k.x&&t.y==k.y){
			d=-1;
		}
	while(d!=-1){
		l++;
		if(l==4){
		l=0;
		t=ta.front();
		k=ka.front();
		ka.pop();
		ta.pop();
		Z.pop();
		A[t.x][t.y][k.x][k.y]=1;
		}
		if(c==100||Z.empty()){
			printf("NA");
		break;
		}
	
		// ?????\????????????????????¨?????¨??????
		t=ta.front();
		k=ka.front();
		c=Z.front();
		
		t.x=t.x+tx[l];
		t.y=t.y+ty[l];
		k.x=k.x+kx[l];
		k.y=k.y+ky[l];
		
		if(D[t.x][t.y]==1){
		t.x=t.x-tx[l];
		t.y=t.y-ty[l];
		}
		if(D[k.x][k.y]==1){
		k.x=k.x-kx[l];
		k.y=k.y-ky[l];
		}
		if(A[t.x][t.y][k.x][k.y]==1){
			continue;
		}
		
		ta.push(t);
		ka.push(k);
		c=c+1;
		Z.push(c);
		
		if(t.x==k.x&&t.y==k.y){
			printf("%d\n",Z.back());
			break;
		}	
		
		
	}
	while(!ka.empty()){
	ka.pop();
	ta.pop();
	Z.pop();
	}
	c=0;
	l=-1;
	scanf("%d %d",&w,&h);
	}	
	return 0;

}

C++: #include<bits/stdc++.h>
#define P pair<int,int>
using namespace std;

int dx[4] = { -1,0,0,1 }, dy[4] = { 0,-1,1,0 };
int main() {
	int a, b;
	while (cin >> b>>a, a | b) {
		int c, d, e, f;
		cin >> c >> d >> e >> f;
		c--; d--; e--; f--;
		bool ba[50][50];
		int k[50][50];
		memset(k, -1, sizeof(k));
		for (int g = 0; g < a; g++) {
			for (int h = 0; h < b; h++) {
				cin >> ba[g][h];
			}
		}
		if ((((c - e) & 1) == 0) && (((d - f) & 1) == 0)) {
			queue<P>Q;
			if (!ba[c][d] && !ba[e][f]) {
				Q.push(P(c, d));
				k[c][d] = 0;
			}
			while (Q.size()) {
				P o = Q.front(); Q.pop();
				for (int i = 0; i < 4; i++) {
					int x = dx[i],y=dy[i];
						if (o.first + x >= 0 && o.first + x < a&&o.second + y >= 0 && o.second + y < b) {
							if (c + e - (o.first + x) >= 0 && c + e - (o.first + x) < a&&d + f - (o.second + y) >= 0 && d + f - (o.second + y) < b) {
								if (!ba[o.first + x][o.second + y] && !ba[c + e - (o.first + x)][d + f - (o.second + y)] && k[o.first + x][o.second + y] == -1) {
									Q.push(P(o.first + x, o.second + y));
									k[o.first + x][o.second + y] = k[o.first][o.second] + 1;
								}
							}
						}
				}
			}
			for (int n = 0; n < a; n++) {
				for (int m = 0; m < b; m++) {
					cout << k[n][m]<<" ";
				}
				cout << endl;
			}
		}
		else puts("NA");
	}
}