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 <vector>
#include <algorithm>
#include <queue>
#include <cstring>

#define REP(i,k,n) for(int i=k;i<n;i++)
#define rep(i,n) for(int i=0;i<n;i++)
#define INF 1<<30

using namespace std;

int dx[4] = {1,0,-1,0};
int dy[4] = {0,1,0,-1};

struct Data
{
	int tx,ty,kx,ky,cost;

	Data(int tx,int ty,int kx,int ky,int cost) : tx(tx),ty(ty),kx(kx),ky(ky),cost(cost) {}
};

int main()
{
	int x,y;
	while(cin >> x >> y)
	{
		if(x == 0 && y == 0) break;

		int tx,ty,kx,ky;
		cin >> tx >> ty >> kx >> ky;

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

		int field[55][55];
		memset(field,0,sizeof(field));

		rep(i,y) rep(j,x) cin >> field[i][j];

	   	bool used[52][52][52][52];
		rep(i,52) rep(j,52) rep(k,52) rep(l,52) used[i][j][k][l] = false;
		used[tx][ty][kx][ky] = true;

		queue<Data> que;
		que.push(Data(tx,ty,kx,ky,0));
		
		bool flag = false;
		int ans;

		while(que.size())
		{
			Data data = que.front();
			que.pop();

			if(data.cost >= 100) break;

			if(data.tx == data.kx && data.ty == data.ky)
			{
				flag = true;
				ans = data.cost;
				break;
			}

			rep(i,4)
			{
				int ntx = data.tx + dx[i];
				int nty = data.ty + dy[i];
				int nkx = data.kx + dx[(i+2)%4];
				int nky = data.ky + dy[(i+2)%4];

				Data nd(data.tx,data.ty,data.kx,data.ky,data.cost+1);

				if(0 <= ntx && ntx < x && 0 <= nty && nty < y && field[nty][ntx] == 0)
				{
					nd.tx = ntx;
					nd.ty = nty;
				}

				if(0 <= nkx && nkx < x && 0 <= nky && nky < y && field[nky][ntx] == 0)
				{
					nd.kx = nkx;
					nd.ky = nky;
				}

				if(!used[nd.tx][nd.ty][nd.kx][nd.ky])
				{
					used[nd.tx][nd.ty][nd.kx][nd.ky] = true;
					que.push(nd);
				}
			}

		}

		if(flag) cout << ans << endl;
		else cout << "NA" << endl;
	}
}

C++: #include <iostream>
#include <cstdio>
#include <cstdlib>
#include <math.h>
#include <vector>
#include <queue>
#include <algorithm>
#include <sstream>
#include <string>
using namespace std;
#define FOR(I,N) for(int I = 0; I < (int)(N); I++)
#define FIN(V) cout<<V<<endl
#define pb push_back
#define INF (1 << 30)
typedef pair<int, int> P;
int dx[4] = {1, -1, 0, 0};
int dy[4] = {0, 0, 1, -1};
int w, h, tx, ty, kx, ky;
int maps[51][51];
int memo[51][51][51][51];

struct Data{
    P pt, pk;
    int cnt;
    Data(P pt_, P pk_, int cnt_){
        pt = pt_;
        pk = pk_;
        cnt = cnt_;
    }
    Data(){}
};

int bfs(){
    int ans = INF;
    fill_n(***memo, 51*51*51*51, INF);
    queue<Data> que;
    que.push(Data(P(tx,ty), P(kx, ky), 0));
    while(que.size()){
        Data data = que.front();
        que.pop();
        int x1 = data.pt.first;
        int y1 = data.pt.second;
        int x2 = data.pk.first;
        int y2 = data.pk.second;
        int cost = data.cnt;
        if(cost > 100)break;
        if(memo[x1][y1][x2][y2] >= cost)continue;
        memo[x1][y1][x2][y2] = cost;
        if(x1 == x2 && y1 == y2){ans = cost;break;};
        FOR(i, 4){
            int nx1 = x1 + dx[i];
            int ny1 = y1 + dy[i];
            int nx2 = x2 - dx[i];
            int ny2 = y2 - dy[i];            
            if(maps[ny1][nx1] == 1){nx1 = x1;ny1 = y1;};
            if(maps[ny2][nx2] == 1){nx2 = x2;ny2 = y2;};
            que.push(Data(P(nx1,ny1), P(nx2, ny2), cost+1));
        }
    }

    return ans;
}

int main(void){
    while(cin >> w >> h, w){
        cin >> tx >> ty;
        cin >> kx >> ky;
        fill_n(*maps, 51*51, 1);
        FOR(i, h)FOR(j, w){
            cin >> maps[i+1][j+1];
        }
        int a = bfs();
        if(a >= 100){
            cout << "NA" << endl;
        }else{
            cout << a << endl;
        }
    }
    return 0;    
}

C++: #include<iostream>
#include<string>
#include<vector>
#include<queue>
#define p pair<int,int>
#define P pair<p,p>
using namespace std;

int a[50][50][50][50];
int x[4] = { -1,0,0,1 }, y[4] = { 0,-1,1,0 };
int S[50][50];
signed main() {
	int b, c;
	while (cin >> c >> b, b | c) {
		memset(a, 0x3f, sizeof(a));
		int d, e, f, g; cin >> e >> d >> g >> f; d--; e--; f--; g--;
		a[d][e][f][g] = 0;
		for (int i = 0; i < b; i++) {
			for (int j = 0; j < c; j++) {
				scanf("%d", &S[i][j]);
			}
		}
		queue<P>Q;
		Q.push(P(p(d,e),p(f,g)));
		while (Q.size()) {
			P t = Q.front(); Q.pop();
			for (int i = 0; i < 4; i++) {
				int j = 3 - i;
				p n, m; n = t.first; m = t.second;
				n.first += x[i]; n.second += y[i];
				m.first += x[j]; m.second += y[j];
				if (n.first < 0 || n.first >= b || n.second < 0 || n.second >= c||S[n.first][n.second]==1) {
					n.first -= x[i]; n.second -= y[i];
				}
				if (m.first < 0 || m.first >= b || m.second < 0 || m.second >= c||S[m.first][m.second]==1) {
					m.first -= x[j]; m.second -= y[j];
				}
				if (a[n.first][n.second][m.first][m.second] == 1061109567) {
					a[n.first][n.second][m.first][m.second] = a[t.first.first][t.first.second][t.second.first][t.second.second]+1;
					Q.push(P(p(n.first,n.second),p(m.first,m.second)));
				}
			}
		}
		int MIN = 100;
		for (int i = 0; i < b; i++) {
			for (int j = 0; j < c; j++) {
				MIN = min(MIN, a[i][j][i][j]);
			}
		}
		if (MIN == 100)puts("NA");
		else cout << MIN << endl;
	}
}