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 := 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<iostream>
#include<string>
#include<map>
#include<queue>

#define rep(i,n) for(int i=0;i<int(n);i++)
#define sint(i) scanf("%d",&i);
#define sintt(i,j) scanf("%d%d",&i,&j);
using namespace std;

int xx,yy;

class Q{
	public:
	int bx,by,bbx,bby;
	int dep;
	Q(int bx,int by,int bbx,int bby,int dep):
	bx(bx),by(by),bbx(bbx),bby(bby),dep(dep){}
};

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

int masu[51][51];
int memo[51][51][51][51];

int search(int bx,int by,int bbx,int bby){
	
	queue<Q> hako;
	
	hako.push(Q(bx,by,bbx,bby,0));
	
	while(1){
		if(hako.empty()==1){
			break;
		}
		
		Q u=hako.front();
		hako.pop();
		
		if(u.dep>=100){
			break;
		}
		
		if(u.bx<=0 || u.by<=0 || u.bx>xx || u.by>yy ){
			continue;
		}
		if(u.bbx<=0 || u.bby<=0 || u.bbx>xx || u.bby>yy){
			continue;
		}
		if(masu[u.bx][u.by]==1 || masu[u.bbx][u.bby]==1){
			puts("fsdafasdf");
			continue;
		}
		
		
		if(memo[u.bx][u.by][u.bbx][u.bby]==1){
			continue;
		}else{
			memo[u.bx][u.by][u.bbx][u.bby]=1;
		}
		
		/*
		puts("");
		rep(i,xx){
			rep(j,yy){
				if(i+1==u.by && j+1==u.bx){
					printf("4 ");
					continue;
				}
				if(i+1==u.bby && j+1==u.bbx){
					printf("5 ");
					continue;
				}
				printf("%d ",masu[j+1][i+1]);
			}puts("");
		}*/
		
		if(u.bx==u.bbx && u.by==u.bby){
			return u.dep;
		}
		
		
		rep(i,4){
			int ddx=dx[i],ddy=dy[i];
			if(masu[u.bx+ddx][u.by+ddy]==1) ddx=ddy=0;
			
			int ddxx=dx[(i+2)%4],ddyy=dy[(i+2)%4];
			if(masu[u.bbx+ddxx][u.bby+ddyy]==1) ddxx=ddyy=0;
			hako.push(Q(u.bx+ddx,u.by+ddy,u.bbx+ddxx,u.bby+ddyy,u.dep+1));
		}
	}
	return -1;
}

int main(){
	while(1){
		sintt(xx,yy);
		
		if(xx==0){
			break;
		}
		int bx,by,bbx,bby;
		sintt(bx,by);
		sintt(bbx,bby);
		
		rep(i,51)rep(j,51)rep(k,51)rep(p,51){
		memo[i][j][k][p]=0;
		}
		
		rep(i,yy){
			rep(j,xx){
				sint(masu[j+1][i+1]);
			}
		}
		
		int ans=search(bx,by,bbx,bby);
		if(ans==-1){
			puts("NA");
		}else{
			printf("%d\n",ans);
		}
	}
}

C++: #include <iostream>
#include <queue>
#include <map>
using namespace std;
 
class Point2{
public:
    int tx;
    int ty;
    int kx;
    int ky;
};
 
int mk(Point2 p)        
{
    return (((p.tx-1)*50+(p.ty-1))*50+(p.kx-1))*50+(p.ky-1);
}
 
int main()
{
    while(true){
        int W, H;
        cin >> W >> H;
 
        if(W==0 && H==0)
            break;
 
        Point2 p;
        cin >> p.tx >> p.ty;
        cin >> p.kx >> p.ky;
 
        int d[52][52];
        for(int y=0; y<=H+1; y++){
            for(int x=0; x<=W+1; x++){
                d[y][x] = 1;           
            }
        }
 
        for(int y=1; y<=H; y++){
            for(int x=1; x<=W; x++){
                cin >> d[y][x];
            }
        }
 
        queue<Point2> que;        
        que.push(p);
 
        map<int, int> n;        
        n[mk(p)] = 0;
 
        while(true){
            if(que.empty()){           
                cout << "NA" << endl;
                break;
            }
 
            p = que.front();
            que.pop();
 
            if(n[mk(p)]>=100){      
                cout << "NA" << endl;
                break;
            }
 
            if(p.tx==p.kx && p.ty==p.ky){       
                cout << n[mk(p)] << endl;
                break;
            }
 
            Point2 q;
 
            q = p;
            if(d[q.ty][q.tx+1]==0){
                q.tx = q.tx+1;
            }
            if(d[q.ky][q.kx-1]==0){
                q.kx = q.kx-1;
            }
            if(n.find(mk(q))==n.end()){
                que.push(q);
                n[mk(q)] = n[mk(p)]+1;
            }
 
            q = p;
            if(d[q.ty][q.tx-1]==0){
                q.tx = q.tx-1;
            }
            if(d[q.ky][q.kx+1]==0){
                q.kx = q.kx+1;
            }
            if(n.find(mk(q))==n.end()){
                que.push(q);
                n[mk(q)] = n[mk(p)]+1;
            }
 
            q = p;
            if(d[q.ty+1][q.tx]==0){
                q.ty = q.ty+1;
            }
            if(d[q.ky-1][q.kx]==0){
                q.ky = q.ky-1;
            }
            if(n.find(mk(q))==n.end()){
                que.push(q);
                n[mk(q)] = n[mk(p)]+1;
            }
 
            q = p;
            if(d[q.ty-1][q.tx]==0){
                q.ty = q.ty-1;
            }
            if(d[q.ky+1][q.kx]==0){
                q.ky = q.ky+1;
            }
            if(n.find(mk(q))==n.end()){
                que.push(q);
                n[mk(q)] = n[mk(p)]+1;
            }
        }
    }
 
    return 0;
}