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<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 (flag == 0) {
			cout << "NA" << endl;
		}while (!q.empty()) q.pop();
		flag = 0;
		fill(same[0][0][0], same[51][0][0], 0);
		cin >> X >> Y;
	}
	return 0;
}

C++: #include <bits/stdc++.h>

using namespace std;

struct People {
    int cnt;
    int tx, ty;
    int kx, ky;
};

int ans;
int X, Y;
int tx, ty;
int kx, ky;
int graph[50][50];
int check[50][50][50][50];
int vx[] = {0, 1, 0, -1};
int vy[] = {-1, 0, 1, 0};

int main() {

    while(cin >> X >> Y, X || Y) {

        ans = -1;
        memset(check, 0, sizeof(check));

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

        for(int i = 0; i < Y; ++i) {
            for(int j = 0; j < X; ++j) {
                cin >> graph[i][j];
            }
        }

        queue<People> q;
        q.push((People){0, tx, ty, kx, ky});
        check[tx][ty][kx][ky] = 1;

        while(!q.empty()) {

            People now = q.front(); q.pop();
            check[now.tx][now.ty][now.kx][now.ky] = 1;

            if(now.tx == now.kx && now.ty == now.ky) {
                if(now.cnt >= 100) {
                    break;
                }
                ans = now.cnt;
                break;
            }

            for(int i = 0; i < 4; ++i) {

                People next = now;
                next.cnt++;
                next.tx += vx[i];
                next.ty += vy[i];
                next.kx += vx[i] * -1;
                next.ky += vy[i] * -1;

                if( next.tx >= 0 && next.tx < X && next.ty >= 0 && next.ty < Y && !graph[next.ty][next.tx] &&
                    next.kx >= 0 && next.kx < X && next.ky >= 0 && next.ky < Y && !graph[next.ky][next.kx] &&
                    !check[next.tx][next.ty][next.kx][next.ky]) {

                    q.push(next);

                } else if(  next.tx >= 0 && next.tx < X && next.ty >= 0 && next.ty < Y && !graph[next.ty][next.tx] &&
                            (next.kx < 0 || next.kx >= X || next.ky < 0 || next.ky >= Y || graph[next.ky][next.kx]) && !check[next.tx][next.ty][now.kx]
[now.ky]) {

                    next.kx = now.kx;
                    next.ky = now.ky;
                    q.push(next);

                } else if(  next.kx >= 0 && next.kx < X && next.ky >= 0 && next.ky < Y && !graph[next.ky][next.kx] &&
                            (next.kx < 0 || next.kx >= X || next.ky < 0 || next.ky >= Y || graph[next.ky][next.kx]) && !check[now.tx][now.ty][next.kx][
next.ky]) {

                    next.tx = now.tx;
                    next.ty = now.ty;
                    q.push(next);

                }

            }

        }

        if(ans == -1) {
            cout << "NA" << endl;
        } else {
            cout << ans << endl;
        }

    }

}