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 <vector>
#include <cstring>
#include <iostream>
using namespace std;
int H, W, ax, ay, bx, by, x[52][52], dp[52][52][52][52];
int dx[4] = {0, 1, 0, -1}, dy[4] = {1, 0, -1, 0};
int main() {
	while(cin >> W >> H >> ax >> ay >> bx >> by) {
		for(int i = 0; i < H + 2; i++) {
			for(int j = 0; j < W + 2; j++) {
				x[i][j] = 1;
				if(i && i != H + 1 && j && j != W + 1) scanf("%d", &x[i][j]);
			}
		}
		memset(dp, -1, sizeof(dp)); dp[ay][ax][by][bx] = 0;
		queue<vector<int> > que; que.push({ax, ay, bx, by});
		bool flag = false;
		while(!que.empty()) {
			vector<int> v1 = que.front(); que.pop();
			for(int i = 0; i < 4; i++) {
				vector<int> v2 = v1;
				if(!x[v1[1] + dy[i]][v1[0] + dx[i]]) v2[0] += dx[i], v2[1] += dy[i];
				if(!x[v1[3] - dy[i]][v1[2] - dx[i]]) v2[2] -= dx[i], v2[3] -= dy[i];
				if(v2[0] == v2[2] && v2[1] == v2[3]) {
					flag = true; break;
				}
				if(dp[v2[1]][v2[0]][v2[3]][v2[2]] == -1) {
					dp[v2[1]][v2[0]][v2[3]][v2[2]] = dp[v1[1]][v1[0]][v1[3]][v1[2]] + 1;
					que.push(v2);
				}
			}
			if(dp[v1[1]][v1[0]][v1[3]][v1[2]] >= 100) break;
			if(flag) {
				cout << dp[v1[1]][v1[0]][v1[3]][v1[2]] + 1 << endl; break;
			}
		}
		if(!flag) cout << "NA" << endl;
	}
}

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

int table[51][51];

bool memo[51][51][51][51];

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;

        tx--;ty--;kx--;ky--;

        for(int i=0;i<51;i++){
            for(int j=0;j<51;j++){
                table[i][j] = 1;
                for(int k=0;k<51;k++){
                    for(int r=0;r<51;r++){
                        memo[i][j][k][r] = false;
                    }
                }
            }
        }

        for(int i=0;i<h;i++){
            for(int j=0;j<w;j++){
                //scanf(" %d",&table[i][j]);
                cin >> table[j][i];
                if(table[i][j] == 1){
                    for(int k=0;k<51;k++){
                        for(int r=0;r<51;r++){
                            memo[i][j][k][r] = true;
                        }
                    }
                }
            }
        }

        /*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(memo[v[0]][v[1]][v[2]][v[3]]){
                continue;
            }

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

            q.push(v);

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

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

            q.push(v);


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

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

            q.push(v);

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

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

             q.push(v);
        }

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



    }

    return 0;
}