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.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 {
		heap.Init(&pq)
		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<cstring>
#include<iostream>
#include<vector>
#include<algorithm>
#include<queue>
#include<stack>
using namespace std;
struct P{
  P(){};
  P(int a,int b){
    x=a,y=b;
  }
  int x,y;
  void move(int,int);
};
struct S{
  S(){};
  S(P a,P b){
    t=a;
    k=b;
  }
  P t,k;
  void move(int);
};
 
P size;
S f_pos;
vector<vector<int> > f;
bool input(){
  size=P();
  f_pos=S();
  f.clear();
  cin>>size.y>>size.x;
  if(size.x==0&&size.y==0)return false;
  cin>>f_pos.t.y>>f_pos.t.x;
  cin>>f_pos.k.y>>f_pos.k.x;
  vector<int> t;
  for(int i=0;i<size.y+2;i++){
    t.push_back(1);
  }
  f.push_back(t);
  for(int i=0;i<size.x;i++){
    vector<int> tt;
    tt.push_back(1);
    for(int j=0;j<size.y;j++){
      int tmp;
      cin>>tmp;
      tt.push_back(tmp);
    }
    tt.push_back(1);
    f.push_back(tt);
  }
  f.push_back(t);
  return true;
}
int cost[60][60][60][60];
const int vx[]={0,0,1,-1};
const int vy[]={1,-1,0,0};
void S::move(int i){
  t.move(vx[i],vy[i]);
  k.move(-vx[i],-vy[i]);
}
void P::move(int a,int b){
  if(f[x+a][y+b]!=1){
    x+=a;
    y+=b;
  }
}
int solve(){
  memset(cost,-1,sizeof(cost));
  queue<S> q;
  q.push(f_pos);
  cost[f_pos.t.x][f_pos.t.y][f_pos.k.x][f_pos.k.y]=0;
  while(!q.empty()){
    S now = q.front();q.pop();
    for(int i=0;i<4;i++){
      S tmp = now;
      tmp.move(i);
      if(cost[tmp.t.x][tmp.t.y][tmp.k.x][tmp.k.y]!=-1)continue;
 
      cost[tmp.t.x][tmp.t.y][tmp.k.x][tmp.k.y] = cost[now.t.x][now.t.y][now.k.x][now.k.y]+1;
      if(cost[tmp.t.x][tmp.t.y][tmp.k.x][tmp.k.y]>=100){
        return -1;
      }else if( (tmp.t.x==tmp.k.x)&&(tmp.t.y==tmp.k.y) ){
        return cost[tmp.t.x][tmp.t.y][tmp.k.x][tmp.k.y];
      }else{
        q.push(tmp);
      }
    }
  }
  return -1;
}
int main(){
  while(input()){
    /*
    for(int i=0;i<f.size();i++){
      for(int j=0;j<f[i].size();j++){
        cout<<f[i][j];
      }cout<<endl;
    }cout<<endl;
    */
    int ans= solve();
    if(ans==-1||ans>=100){
      cout<<"NA"<<endl;
    }else{
      cout<<ans<<endl;
    }
  }
}

C++: #include<iostream>
#include<utility>
#include<queue>
using namespace std;
int dx[4] = { 1,0,-1,0 };
int dy[4] = { 0,1,0,-1 };
int main() {
	int W, H, tx, ty, kx, ky;
	bool d[52][52];
	bool memo[52][52][52][52];
	while (true) {
		cin >> W >> H;
		if (W == 0)break;
		for (int i = 0; i < 52; i++) {
			for (int j = 0; j < 52; j++) {
				for (int k = 0; k < 52; k++) {
					for (int l = 0; l < 52; l++) {
						memo[i][j][k][l] = false;
					}
				}
			}
		}
		for (int i = 0; i < 52; i++) {
			for (int j = 0; j < 52; j++) {
				d[i][j] = 1;
			}
		}
		cin >> tx >> ty >> kx >> ky;
		for (int i = 1; i < H + 1; i++) {
			for (int j = 1; j < W + 1; j++) {
				cin >> d[j][i];
			}
		}
		pair<pair<int, int>, pair<int, int> >num;
		num.first.first = tx;
		num.first.second = ty;
		num.second.first = kx;
		num.second.second = ky;
		queue<pair<pair<int, int>, pair<int, int> > > q;
		q.push(num);
		int qsize = q.size();
		int loopcount = 0;
		while (!q.empty()) {
			num = q.front();
			q.pop();
			if (qsize == 0) {
				qsize = q.size()+1;
				loopcount++;
				if (loopcount == 100) {
					cout << "NA" << endl;
					break;
				}
			}
			qsize--;
			memo[num.first.first][num.first.second][num.second.first][num.second.second] = true;
			memo[num.second.first][num.second.second][num.first.first][num.first.second] = true;
			if (num.first.first == num.second.first && num.first.second == num.second.second) {
				cout << loopcount << endl;
				break;
			}
			for (int i = 0; i < 4; i++) {
				pair<pair<int, int>, pair<int, int> >copy;
				copy = num;
				copy.first.first += dx[i];
				copy.first.second += dy[i];
				if (d[copy.first.first][copy.first.second]) {
					copy.first.first -= dx[i];
					copy.first.second -= dy[i];
				}
				copy.second.first -=dx[i];
				copy.second.second -= dy[i];
				if (d[copy.second.first][copy.second.second]) {
					copy.second.first += dx[i];
					copy.second.second += dy[i];
				}
				if (!memo[copy.first.first][copy.first.second][copy.second.first][copy.second.second]) {
					q.push(copy);
				}
			}
			if (q.empty()) {
				cout << "NA" << endl;
			}
		}
	}
	return 0;
}