Go: package main

import (
	"container/heap"
	"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 (pq PQStatus) Len() int {
	return len(pq)
}
func (pq PQStatus) Less(i, j int) bool {
	if pq[i].Turn == pq[j].Turn {
		return pq[i].Person.Distance() < pq[j].Person.Distance()
	}
	return pq[i].Turn < pq[j].Turn
}

func (pq PQStatus) Swap(i, j int) {
	pq[i], pq[j] = pq[j], pq[i]
}

func (pq *PQStatus) Push(x interface{}) {
	item := x.(*Status)
	*pq = append(*pq, item)
}

func (pq *PQStatus) Pop() interface{} {
	old := *pq
	n := len(old)
	item := old[n-1]
	*pq = old[0 : n-1]
	return item
}

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)
	heap.Init(&pq)
	heap.Push(&pq, start)
	dx := []int64{0, 1, 0, -1}
	dy := []int64{1, 0, -1, 0}
	memo := make(map[PersonPosition]struct{}, 0)
	for pq.Len() > 0 {
		now := heap.Pop(&pq).(*Status)
		if now.Person.Distance() == 0 {
			fmt.Println(now.Turn)
			return
		}
		if _, ok := memo[now.Person]; ok {
			continue
		}
		memo[now.Person] = struct{}{}
		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 += 1
			if next.Turn <= 100 {
				heap.Push(&pq, next)
			}
		}
	}
	fmt.Println("NA")
}

func main() {
	var h, w int64
	for {
		fmt.Scan(&h, &w)
		if h == 0 && w == 0 {
			break
		}
		solve(h, w)
	}
}

C++: #include<map>
#include<set>
#include<list>
#include<cmath>
#include<queue>
#include<stack>
#include<cstdio>
#include<string>
#include<vector>
#include<complex>
#include<cstdlib>
#include<cstring>
#include<numeric>
#include<sstream>
#include<iostream>
#include<algorithm>
#include<functional>

#define mp       make_pair
#define pb       push_back
#define all(x)   (x).begin(),(x).end()
#define rep(i,n) for(int i=0;i<(n);i++)
#define REP(i,b,n) for(int i=b;i<n;i++)

using namespace std;

typedef    long long          ll;
typedef    unsigned long long ull;
typedef    vector<bool>       vb;
typedef    vector<int>        vi;
typedef    vector<vb>         vvb;
typedef    vector<vi>         vvi;
typedef    pair<int,int>      pii;

const int INF=1<<29;
const double EPS=1e-9;

const int dx[]={1,0,-1,0},dy[]={0,-1,0,1};
int X,Y;
int tx,ty;
int kx,ky;
int board[55][55];
typedef pair<pii,pii> P;
int main(){
	while(cin>>X>>Y,X||Y){
		queue<P> que;
		queue<int> kai;
		cin>>tx>>ty;
		cin>>kx>>ky;
		rep(i,Y+1){
			rep(j,X+1){
				board[i][j] = 0;
			}
		}

		for(int i = 1;i <= Y;i++){
			for(int j  =1;j <= X;j++){
				cin>>board[i][j];
			}
		}
		/*for(int i = 1;i <= Y;i++){
			for(int j  =1;j <= X;j++){
				cout<<board[i][j];
			}
			cout <<endl;
		}*/
		que.push(P(pii(tx,ty),pii(kx,ky)));
		kai.push(0);
		int ans = 200;
		map<P,int> ma;
		ma.clear();
		while(!que.empty()){
			int ptx = que.front().first.first;
			int pty = que.front().first.second;
			int pkx = que.front().second.first;
			int pky = que.front().second.second;
			int sum = kai.front();
			que.pop();
			kai.pop();
			//cout <<sum<<endl;
			if(sum>=100){
				continue;
			}
			if(ptx==pkx&&pty==pky){
				ans = min(ans,sum);
				continue;
			}
			ma[P(pii(ptx,pty),pii(pkx,pky))] = 1;
			for(int i = 0;i < 4;i++){
				int ntx =ptx +dx[i];
				int nty =pty +dy[i];
				int nkx =pkx +dx[(i+2)%4];
				int nky =pky+dy[(i+2)%4];
				if(ma[P(pii(ntx,nty),pii(nkx,nky))] ==1){
					continue;
				}
				if(ntx>X||ntx<=0||nty>Y||nty<=0||board[nty][ntx]==1){
					nty = pty;
					ntx = ptx;

					//cout <<nty<<" "<<ntx<<endl;
				}
				if(nky>Y||nky<=0||nkx>X||nkx<=0||board[nky][nkx]==1){
					nky = pky;
					nkx = pkx;
				}
				if(ma[P(pii(ntx,nty),pii(nkx,nky))] ==1){
					continue;
				}
				ma[P(pii(ntx,nty),pii(nkx,nky))] = 1;
				que.push(P(pii(ntx,nty),pii(nkx,nky)));
				kai.push(sum+1);
			}
		}
		if(ans==200){
			cout<<"NA"<<endl;
		}else{
			cout <<ans<<endl;
		}
	}
	return 0;
}

C++: #include<queue>
#include<iostream>
#include<algorithm>
#include<cstring>
#include<cstdio>
using namespace std;
int dy[]={1,-1,0,0};
int dx[]={0,0,1,-1};
// 構造体
struct P{
  int ty;
  int tx;
  int ky;
  int kx;
  int c;
  P(int ty,int tx,int ky,int kx,int c):ty(ty),tx(tx),ky(ky),kx(kx),c(c){}
};
int bfs(int ty,int tx,int ky,int kx);
int g[51][51];
int d[51][51][51][51]; // フラグ
int x,y;
int main(){
  int tx,ty;
  int kx,ky;
  while(1){
    cin >> x >> y;
    if(!x && !y)break;
    cin >> tx >> ty;
  cin >> kx >> ky;
  for(int i=0;i<y;i++){
    for(int j=0;j<x;j++){
      cin >> g[i][j];
    }
  }
  int ret = bfs( ty - 1 , tx - 1 , ky - 1 , kx - 1 );
  if(ret != -1){
    cout << ret << endl;
  }else {
    cout << "NA" << endl;
  }
    memset( d , 0 , sizeof(d) );
  }
}
int bfs(int ty,int tx,int ky,int kx){
  queue<P> que;
  que.push(P(ty,tx,ky,kx,0));
  d[ty][tx][ky][kx] = 1;

  while(!que.empty()){
    P p = que.front();que.pop();
    // 終了判定
    if(p.c >= 100)return -1;
    if(p.ty == p.ky && p.tx == p.kx)return p.c;
     for(int i=0;i<4;i++){
      int tty = p.ty + dy[i];
      int ttx = p.tx + dx[i];
      int kky = p.ky + (dy[i] * -1); // 　↓
      int kkx = p.kx + (dx[i] * -1); // 逆方向

      // 両方いけるとき
      if(0<=tty && tty<y && 0<=ttx && ttx<x){
        if(0<=kky && kky<y && 0<=kky && kkx<x){
          if(d[tty][ttx][kky][kkx] == 0  && g[tty][ttx] == 0 && g[kky][kkx] == 0){
            que.push(P(tty,ttx,kky,kkx,p.c+1));
            d[tty][ttx][kky][kkx] = 1;
          }
        }
      }
      // たかゆきくんだけいけるとき
      if(0<=tty && tty<y && 0<=ttx && ttx<x){
        if(0>kky || kky>=y || 0>kky || kkx>=x || g[kky][kkx] == 1){
          if(d[tty][ttx][p.ky][p.kx] == 0 && g[tty][ttx] == 0){
            que.push(P(tty,ttx,p.ky,p.kx,p.c+1));
            d[tty][ttx][p.ky][p.kx] = 1;
          }
        }
      }
      // 一之君だけいけるとき
       if(0<=kky && kky<y && 0<=kkx && kkx<x){
        if(0>tty || tty>=y || 0>tty || ttx>=x || g[tty][ttx] == 1){
          if(d[p.ty][p.tx][kky][kkx] == 0 && g[kky][kkx] == 0){
            que.push(P(p.ty,p.tx,kky,kkx,p.c+1));
            d[p.ty][p.tx][kky][kkx] = 1;
          }
        }
      }
    }
  }
  return -1;
}