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 "bits/stdc++.h"
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define all(a) (a).begin(),(a).end()
#define pb emplace_back
#define INF (1e9+1)

int w,h;
int v[51][51];

struct Pos{
    int ay,ax,by,bx;
    
    bool operator < (Pos obj) const{
        int t = ay + ax*60 + by*60*60 + bx*60*60*60;
        int p = obj.ay + obj.ax*60 + obj.by*60*60 + obj.bx*60*60*60;
        return t<p;
    }
    
};

int main(){
    while(cin>>w>>h&&(w||h)){
        int ax,ay,bx,by;
        cin>>ax>>ay>>bx>>by;
        ax--,ay--,bx--,by--;
        
        rep(i,h)rep(j,w)cin>>v[i][j];
        
        int dy[]={1,0,-1,0};
        int dx[]={0,1,0,-1};
        
        map<Pos,int> mp;
        queue<Pos> que;
        
        mp[Pos{ay,ax,by,bx}] = 0;
        que.push( Pos{ay,ax,by,bx} );
        
        while(que.size()){
            Pos q = que.front();
            int iy = q.ay, ix = q.ax;
            int jy = q.by, jx = q.bx;
            
            rep(k,4){
                int ddix = ix+dx[k];
                int ddjx = jx-dx[k];
                int ddiy = iy+dy[k];
                int ddjy = jy-dy[k];
                
                if(ddiy<0 || ddiy>=h || ddix<0 || ddix>=w || v[ddiy][ddix])ddiy = iy, ddix = ix;
                if(ddjy<0 || ddjy>=h || ddjx<0 || ddjx>=w || v[ddjy][ddjx])ddjy = jy, ddjx = jx;
                
                if( mp.count( Pos{ddiy, ddix, ddjy, ddjx} )==0 || mp[Pos{ddiy, ddix, ddjy, ddjx}]>mp[Pos{iy, ix, jy, jx}]+1 ){
                    que.push( Pos{ddiy, ddix, ddjy, ddjx} );
                    mp[Pos{ddiy, ddix, ddjy, ddjx}] = mp[Pos{iy, ix, jy, jx}]+1;
                }
            }
            que.pop();
        }
        
        int ans = INF;
        rep(i,h){
            rep(j,w){
                if(mp.count(Pos{i,j,i,j})==0)continue;
                ans = min(ans,mp[Pos{i,j,i,j}]);
            }
        }
        if(ans>=100)cout<<"NA"<<endl;
        else cout<<ans<<endl;
    }
}

C++: #include<queue>
#include<iostream>
#include<algorithm>
using namespace std;
bool same[52][52][52][52] = { 0 };
struct maigo{
	int x[2];// ????????????[0]???????????????[1]
	int y[2];// ????????????[0]???????????????[1]
	int count;
};
int main(){
	queue<maigo> q;
	int tx, ty; int kx, ky;
	int **depart, X, Y;
	int flag = 0, a = 0;
	int c = 0;
	int f = 0;
	cin >> X >> Y;
	while (X != 0 && Y != 0){
		depart = new int*[Y + 2];
		for (int i = 0; i < Y + 2; i++){
			depart[i] = new int[X + 2];
		}
		for (int i = 0; i < Y + 2; i++){
			for (int l = 0; l < X + 2; l++){
				depart[i][l] = 3;
			}
		}
		cin >> tx >> ty;
		cin >> kx >> ky;
		for (int i = 1; i < Y + 1; i++){
			for (int l = 1; l < X + 1; l++){
				cin >> depart[i][l];
			}
		}
		maigo temp;
		temp.x[0] = tx; temp.y[0] = ty;
		temp.x[1] = kx; temp.y[1] = ky;
		temp.count = 1;
		q.push(temp);
		while (!q.empty() && flag == 0){
			maigo t = q.front();
			maigo into;
			q.pop();
			same[t.x[0]][t.y[0]][t.x[1]][t.y[1]] = 1;
			if (t.count >= 100) break;
			int dx1[4] = { 1, 0, -1, 0 }; int dx2[4] = { 0, 1, 0, -1 };
			for (int i = 0; i < 4; i++){
				if (depart[t.x[0] + dx1[i]][t.y[0] + dx2[i]] == 0 &&
					depart[t.x[1] - dx1[i]][t.y[1] - dx2[i]] == 0 &&
					same[t.x[0] + dx1[i]][t.y[0] + dx2[i]][t.x[1] - dx1[i]][t.y[1] - dx2[i]] == 0){
					if (t.x[0] + dx1[i] == t.x[1] - dx1[i] &&
						t.y[0] + dx2[i] == t.y[1] - dx2[i]){
						cout << t.count << endl;
						flag = 1;
					}
					into.x[0] = t.x[0] + dx1[i], into.y[0] = t.y[0] + dx2[i];
					into.x[1] = t.x[1] - dx1[i], into.y[1] = t.y[1] - dx2[i];

					into.count = t.count + 1;
					q.push(into);
				}
				if (depart[t.x[0] + dx1[i]][t.y[0] + dx2[i]] == 0 && //???????????? ok ???????????? no ?????´???
					depart[t.x[1] - dx1[i]][t.y[1] - dx2[i]] != 0 &&
					same[t.x[0] + dx1[i]][t.y[0] + dx2[i]][t.x[1]][t.y[1]] == 0){
					if (t.x[0] + dx1[i] == t.x[1] &&
						t.y[0] + dx2[i] == t.y[1]){
						cout << t.count << endl;
						flag = 1;
					}
					into.x[0] = t.x[0] + dx1[i], into.y[0] = t.y[0] + dx2[i];
					into.x[1] = t.x[1], into.y[1] = t.y[1];

					into.count = t.count + 1;
					q.push(into);
				}
				if (depart[t.x[0] + dx1[i]][t.y[0] + dx2[i]] != 0 && //???????????? no??????????????? yes????????´???
					depart[t.x[1] - dx1[i]][t.y[1] - dx2[i]] == 0 &&
					same[t.x[0]][t.y[0]][t.x[1] - dx1[i]][t.y[1] - dx2[i] == 0]){
					if (t.x[0] == t.x[1] - dx1[i] &&
						t.y[0] == t.y[1] - dx2[i]){
						cout << t.count << endl;
						flag = 1;
					}
					into.x[0] = t.x[0], into.y[0] = t.y[0];
					into.x[1] = t.x[1] - dx1[i], into.y[1] = t.y[1] - dx2[i];
					into.count = t.count + 1;
					q.push(into);
				}
			}
		}if (a == 1 || flag == 0) {
			cout << "NA" << endl;
		}while (!q.empty()) q.pop();
		a = 0; flag = 0;
		fill(same[0][0][0], same[52][0][0], 0);
		cin >> X >> Y;
	}
	return 0;
}