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 <bits/stdc++.h>

using namespace std;

#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
#define fi first
#define se second

template<typename A, typename B> inline bool chmax(A &a, B b) { if (a<b) { a=b; return 1; } return 0; }
template<typename A, typename B> inline bool chmin(A &a, B b) { if (a>b) { a=b; return 1; } return 0; }

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<int, pii> pip;
typedef pair<pii, pii> ppp;
const ll INF = 1ll<<29;
const ll MOD = 1000000007;
const double EPS  = 1e-9;

int W, H;
pii tp, kp;
int maps[50][50];
map<ppp, int> dp;

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

bool ok(pii p) {
	if (!(p.fi >= 0 && p.fi < H && p.se >= 0 && p.se < W)) return false;
	if (maps[p.fi][p.se] == 1) return false;
	return true;
}

int main() {
	while (cin >> W >> H, W || H) {
		cin >> tp.se >> tp.fi >> kp.se >> kp.fi;
		tp.se--; tp.fi--; kp.se--; kp.fi--;
		REP(i, H) REP(j, W) scanf("%d", &maps[i][j]);
		
		dp.clear();
		
		queue<ppp> que;
		que.push(ppp(tp, kp));
		dp[ppp(tp, kp)] = 0;
		int ans = INF;
		
		while (!que.empty()) {
			pii p1 = que.front().fi, p2 = que.front().se;
			que.pop();
			int c = dp[ppp(p1, p2)];
			
			if (p1 == p2) { chmin(ans, c); break; }
			if (c == 100) break;
			
			REP(i, 4) {
				pii np1(p1.fi + dy[i], p1.se + dx[i]);
				pii np2(p2.fi + dy[(i+2)%4], p2.se + dx[(i+2)%4]);
				
				bool o1 = ok(np1), o2 = ok(np2);
				
				if (!o1 && !o2) continue;
				ppp next(o1 ? np1 : p1, o2 ? np2 : p2);
				if (dp.find(next) != dp.end()) continue;
				dp[next] = c + 1;
				que.push(next);
			}
		}
		
		if (ans == INF) puts("NA");
		else cout << ans << endl;
		
	}
	return 0;
}

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

#define rep_(v, f, l) for (int v = (f); v < (l); ++v)
#define rep(v, n) rep_(v, 0, n)
#define lep(v, n) rep_(v, 1, n + 1)

using namespace std;

typedef long long int lint;

static inline int in(){ int x; scanf("%d", &x); return x; }
static inline lint inl(){ lint x; scanf("%lld", &x); return x; }

struct State {
    int tx, ty;
    int kx, ky;
    State(int tx, int ty, int kx, int ky) : tx(tx), ty(ty), kx(kx), ky(ky) {}
    bool isComplete(){
        return tx == kx && ty == ky;
    }
};

int range(int maxi, int x, int mini)
{
    if (maxi <= x) return maxi;
    if (mini >= x) return mini;
    return x;
}

int dx[] = {1, -1, 0, 0};
int dy[] = {0, 0, 1, -1};
char visited[64][64][64][64];

int main()
{
    int w, h;
    while (w = in(), h = in(), w){
        int tx, ty, kx, ky;
        tx = in();
        ty = in();
        kx = in();
        ky = in();

        int field[128][128] = {};
        rep(i, h){
            rep(j, w){
               field[i + 1][j + 1] = in();
            }
        }

        queue<State> Q;
        State init = State(tx, ty, kx, ky);
        Q.push(init);
        memset(visited, 0, sizeof(visited));
        visited[tx][ty][kx][ky] = 1;
        bool ok = false;
        rep(turn, 101){
            queue<State> nQ;
            while (!Q.empty()){
                State state = Q.front();
                Q.pop();
                if (state.isComplete()){
                    ok = true;
                    break;
                }
                rep(i, 4){
                    State n = state;
                    n.tx = range(w, n.tx + dx[i], 1);
                    n.kx = range(w, n.kx - dx[i], 1);
                    n.ty = range(h, n.ty + dy[i], 1);
                    n.ky = range(h, n.ky - dy[i], 1);
                    if (field[n.ty][n.tx]){
                        n.ty = state.ty;
                        n.tx = state.tx;
                    }
                    if (field[n.ky][n.kx]){
                        n.ky = state.ky;
                        n.kx = state.kx;
                    }

                    if (!visited[n.tx][n.ty][n.kx][n.ky]){
                        visited[n.tx][n.ty][n.kx][n.ky] = 1;
                        nQ.push(n);
                    }
                }
            }
            if (ok){
                printf("%d\n", turn);
                break;
            }
            Q = nQ;
        }
        if (!ok){
            puts("NA");
        }
    }
    return (0);
}