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 <queue>
#include <vector>
#include <iostream>

#define INF (1 << 25)

using namespace std;

vector<vector<vector<vector<int> > > > dp;

vector<vector<int> > M;

int H, W, sx1, sy1, sx2, sy2;

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

int bfs()
{
    dp = vector<vector<vector<vector<int> > > >(H, vector<vector<vector<int> > >(W, vector<vector<int> >(H, vector<int>(W, INF)))); dp[sy1][sx1][sy2][sx2] = 0;
    
    queue<pair<pair<pair<int, int>, pair<int, int> >, int> > que; que.push(make_pair(make_pair(make_pair(sx1, sy1), make_pair(sx2, sy2)), 0));
    
    while(!que.empty())
    {
        int x1 = que.front().first.first.first;
        int y1 = que.front().first.first.second;
        int x2 = que.front().first.second.first;
        int y2 = que.front().first.second.second;
        
        int turn = que.front().second;
        
        que.pop();
        
        for(int dir = 0; dir < 4; dir++)
        {
            int tx1 = x1 + dx[dir]; if(tx1 < 0 || tx1 > W) { tx1 -= dx[dir]; }
            int ty1 = y1 + dy[dir]; if(ty1 < 0 || ty1 > H) { ty1 -= dy[dir]; }
            int tx2 = x2 - dx[dir]; if(tx2 < 0 || tx2 > W) { tx2 += dx[dir]; }
            int ty2 = y2 - dy[dir]; if(ty2 < 0 || ty2 > H) { ty2 += dy[dir]; }
            
            if(M[ty1][tx1] == 1) { tx1 -= dx[dir]; ty1 -= dy[dir]; }
            if(M[ty2][tx2] == 1) { tx2 += dx[dir]; ty2 += dy[dir]; }
            
            if(tx1 == tx2 && ty1 == ty2) { return turn + 1; }
            
            if(dp[ty1][tx1][ty2][tx2] == INF)
            {
                dp[ty1][tx1][ty2][tx2] = turn + 1;
                
                que.push(make_pair(make_pair(make_pair(tx1, ty1), make_pair(tx2, ty2)), turn + 1);
            }
        }
    }
    
    return -1;
}

int main()
{
    while(true)
    {
        cin >> W >> H;
        
        if(H == 0 && W == 0) { break; }
        
        M = vector<vector<int> >(H, vector<int>(W));
        
        cin >> sx1 >> sy1 >> sx2 >> sy2;
        
        sx1--; sy1--; sx2--; sy2--;
        
        for(int i = 0; i < H; i++)
        {
            for(int j = 0; j < W; j++)
            {
                cin >> M[i][j];
            }
        }
        
        int Ans = bfs();
        
        cout << (Ans == -1 ? "NA" : Ans) << endl;
    }
    
    return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <queue>
#include <cstring>

using namespace std;

typedef pair<int, int> Pii;
typedef pair<int, pair<Pii, Pii> > Tpl;
#define fi first
#define se second
int W, H;
int const INF = 1<<29;
inline bool inF(int x, int y) {
  return 0<=x&&x<W&&0<=y&&y<H;
}

int main() {

  int const dx[] = {-1,0,1,0};
  int const dy[] = {0,-1,0,1};
  while(cin >> W >> H && (W|H)) {
    int tx, ty, kx, ky; cin >> tx >> ty >> kx >> ky; tx--; ty--; kx--; ky--;
    int grid[51][51];
    for(int i=0; i<H; i++)
      for(int j=0; j<W; j++)
	cin >> grid[i][j];
    
    static int vis[51][51][51][51];
    fill(vis[0][0][0], vis[51][0][0], INF);
    
    queue<Tpl> Q;
    Q.push(Tpl(make_pair(0, make_pair(Pii(tx, ty), Pii(kx, ky)))));
    vis[ty][tx][ky][kx] = 0;
    int ans = -1;
    while(!Q.empty()) {
      Tpl t = Q.front(); Q.pop();
      const int tx = t.se.fi.fi, ty = t.se.fi.se, kx = t.se.se.fi, ky = t.se.se.se;
      const int cost = t.fi;
      for(int i=0; i<4; i++) {
	int ntx = tx+dx[i], nty = ty+dy[i];
	int nkx = kx-dx[i], nky = ky-dy[i];
	if(tx == kx && ty == ky) { ans = cost; goto EXIT; }
	if(!inF(ntx, nty) && !inF(nkx, nky)) continue;
	if(!inF(ntx, nty)) ntx = tx, nty = ty;
	if(!inF(nkx, nky)) nkx = kx, nky = ky;
	if(grid[nty][ntx] && grid[nky][nkx]) continue;
	if(grid[nty][ntx]) ntx = tx, nty = ty;
	if(grid[nky][nkx]) nkx = kx, nky = ky;
	if(vis[nty][ntx][nky][nkx] > cost+1) {
	  if(cost+1 == 100) continue;
	  vis[nty][ntx][nky][nkx] = cost+1;
	  Q.push(Tpl(cost+1, make_pair(Pii(ntx, nty), Pii(nkx, nky))));
	}
      }
    }
    
  EXIT:;
    if(ans == -1) cout << "NA" << endl;
    else cout << ans << endl;
  }
  
  return 0;
}