Go: package main

import (
	"container/heap"
	"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)
	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)
	dx := []int64{0, 1, 0, -1}
	dy := []int64{1, 0, -1, 0}
	memo := make(map[PersonPosition]struct{}, 0)
	for pq.Len() > 0 {
		now := heap.Pop(&pq).(*Status)
		if now.Person.Distance() == 0 {
			fmt.Println(now.Turn)
			return
		}
		if _, ok := memo[now.Person]; ok {
			continue
		}
		memo[now.Person] = struct{}{}
		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)
			}
		}
	}
	fmt.Println("NA")
}

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<algorithm>
using namespace std;
int H,W;
int d[50][50][50][50];
int dx[4]={0,1,0,-1},dy[4]={1,0,-1,0};
int s[50][50];
main()
{
	while(cin>>W>>H,H)
	{
		int tx,ty,kx,ky;
		cin>>ty>>tx>>ky>>kx;
		tx--,ty--,kx--,ky--;
		for(int i=0;i<H;i++)for(int j=0;j<W;j++)cin>>s[i][j];
		for(int i=0;i<H;i++)for(int j=0;j<W;j++)for(int k=0;k<H;k++)for(int l=0;l<W;l++)d[i][j][k][l]=114514;
		d[tx][ty][kx][ky]=0;
		queue<pair<pair<int,int>,pair<int,int> > >P;
		P.push(make_pair(make_pair(tx,ty),make_pair(kx,ky)));
		for(int T=1;T<100;T++)
		{
			queue<pair<pair<int,int>,pair<int,int> > >Q;
			while(!P.empty())
			{
				int x1=P.front().first.first,y1=P.front().first.second;
				int x2=P.front().second.first,y2=P.front().second.second;
				P.pop();
				for(int r=0;r<4;r++)
				{
					int tx1=x1+dx[r],ty1=y1+dy[r];
					int tx2=x2-dx[r],ty2=y2-dy[r];
					if(tx1<0||tx1>=H||ty1<0||ty1>=W||s[tx1][ty1]==1)tx1=x1,ty1=y1;
					if(tx2<0||tx2>=H||ty2<0||ty2>=W||s[tx2][ty2]==1)tx2=x2,ty2=y2;
					if(d[tx1][ty1][tx2][ty2]>T)
					{
						d[tx1][ty1][tx2][ty2]=T;
						Q.push(make_pair(make_pair(tx1,ty1),make_pair(tx2,ty2)));
					}
				}
			}
			P=Q;
		}
		int ans=114514;
		for(int i=0;i<H;i++)for(int j=0;j<W;j++)
		{
			if(ans>d[i][j][i][j])ans=d[i][j][i][j];
		}
		if(ans<100)cout<<ans<<endl;
		else cout<<"NA"<<endl;
	}
}

C++: #include <bits/stdc++.h>
using namespace std;

int table[52][52];

bool memo[52][52][52][52];

const int leftmove = -1;
const int rightmove = 1;
const int upmove = -1;
const int downmove = 1;

int main() {

    while(1){

        int w,h;

        //scanf(" %d %d",&w,&h);

        cin >> w >> h;

        if(w==0&&h==0) break;

        int tx,ty,kx,ky;

        //scanf(" %d %d %d %d",&tx,&ty,&kx,&ky);

        cin >> tx >> ty >> kx >> ky;

        for(int i=0;i<52;i++){
            for(int j=0;j<52;j++){
                for(int k=0;k<52;k++){
                    for(int r=0;r<52;r++){
                        memo[i][j][k][r] = false;
                    }
                }
            }
        }

        for(int i=1;i<=h;i++){
            for(int j=1;j<=w;j++){
                //scanf(" %d",&table[i][j]);
                cin >> table[i][j];
            }
        }

        /*printf("\n");

        for(int i=0;i<h;i++){
            for(int j=0;j<w;j++){
                printf("%d ",table[i][j]);
            }
            printf("\n");
        }*/

        //memset(memo,false,sizeof(memo));

        queue<vector<int> > q;

        vector<int> v(5);

        v[0] = tx; v[1] = ty; v[2] = kx; v[3] = ky; v[4] = 0;

        if(table[v[0]][v[1]] == 1 || table[v[2]][v[3]] == 1){
            cout << "NA" << endl;
            continue;
        }

        q.push(v);

        bool check = false;

        while(!q.empty()){

            v = q.front(); q.pop();

            if(v[0] == v[2] && v[1] == v[3]){
                check = true;
                cout << v[4] << endl;
                break;
            }

            memo[v[0]][v[1]][v[2]][v[3]] = true;

            v[4]++;

            if(v[4] >= 100){
                break;
            }

            vector<int> before(5);

            for(int i=0;i<5;i++){
                before[i] = v[i];
            }

            if(v[0]+leftmove != 0 && table[v[0]+leftmove][v[1]] == 0){
                v[0]+=leftmove;
            }
            if(v[2]+rightmove != w+1 && table[v[2]+rightmove][v[3]] == 0){
                v[2]+=rightmove;
            }

            if(!memo[v[0]][v[1]][v[2]][v[3]]) {
                q.push(v);
            }

            for(int i=0;i<5;i++){
                v[i] = before[i];
            }

            if(v[2]+leftmove != 0 && table[v[2]+leftmove][v[3]] == 0){
                v[2]+=leftmove;
            }
            if(v[0]+rightmove != w+1 && table[v[0]+rightmove][v[1]] == 0){
                v[0]+=rightmove;
            }

            if(!memo[v[0]][v[1]][v[2]][v[3]]) {
                q.push(v);
            }


            for(int i=0;i<5;i++){
                v[i] = before[i];
            }

            if(v[3]+upmove != 0 && table[v[2]][v[3]+upmove] == 0){
                v[3]+=upmove;
            }
            if(v[1]+downmove != h+1 && table[v[0]][v[1]+downmove] == 0){
                v[1]+=downmove;
            }

            if(!memo[v[0]][v[1]][v[2]][v[3]]) {
                q.push(v);
            }

            for(int i=0;i<5;i++){
                v[i] = before[i];
            }

            if(v[1]+upmove != 0 && table[v[0]][v[1]+upmove] == 0){
                v[1]+=upmove;
            }
            if(v[3]+downmove != h+1 && table[v[2]][v[3]+downmove] == 0){
                v[3]+=downmove;
            }

            if(!memo[v[0]][v[1]][v[2]][v[3]]) {
                q.push(v);
            }
        }

        if(!check){
            cout << "NA" << endl;
        }



    }

    return 0;
}