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 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<stdio.h>
#include<iostream>
#include<queue>
#include<string.h>
using namespace std;
struct oza{
	int x;
	int y;
};
int A[50][50][50][50];
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(Z.back()==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<iostream>
#include<queue>
#include<map>
using namespace std;
int dx[4] = { 1,0,-1,0 };
int dy[4] = { 0,1,0,-1 };
class state {
public:
	int tx;
	int ty;
	int kx;
	int ky;
	int time;
	bool operator < (const state &s)const {
		if (ty != s.ty)return ty < s.ty;
		if (tx != s.tx)return tx < s.tx;
		if (ky != s.ky)return ky < s.ky;
		if (kx != s.kx)return kx < s.kx;
		return false;
	}
};
int main() {
	while (true) {
		int W, H;
		cin >> W >> H;
		if (W == 0 && H == 0)
			break;
		bool d[52][52];
		for (int i = 0; i < H + 2; i++) {
			for (int j = 0; j < W + 2; j++) {
				d[i][j] = 1;
			}
		}
		state num;
		cin >> num.tx >> num.ty >> num.kx >> num.ky;
		for (int i = 1; i < H + 1; i++) {
			for (int j = 1; j < W + 1; j++) {
				cin >> d[j][i];
			}
		}
		num.time = 0;
		queue<state> q;
		q.push(num);
		map<state, bool> m;
		m[num] = true;
		while (true) {
			num = q.front();
			q.pop();
			if (num.time >= 100) {
				cout << "NA" << endl;
				break;
			}
			if (num.tx == num.kx && num.ty == num.ky) {
				cout << num.time << endl;
				break;
			}
			for (int i = 0; i < 4; i++) {
				state copy = num;
				copy.time += 1;
				if (d[copy.ty + dy[i]][copy.tx + dx[i]] == 0) {
					copy.ty += dy[i];
					copy.tx += dx[i];
				}
				if (d[copy.ky - dy[i]][copy.kx - dx[i]] == 0) {
					copy.ky -= dy[i];
					copy.kx -= dx[i];
				}
				if (m.find(copy)==m.end()) {
					q.push(copy);
					m[copy] = true;
				}
			}
			if (q.empty()) {
				cout << "NA" << endl;
				break;
			}
		}
		m.clear();
		while (!q.empty()) {
			q.pop();
		}
	}
	return 0;
}