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;
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;
}

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<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;

}