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<iostream>
#include<set>
#include<queue>
#include<vector>
#include<sstream>
#include<algorithm>
using namespace std;
#define REP(i,b,n) for(int i=b;i<n;i++)
#define rep(i,n)   REP(i,0,n)
#define pb         push_back

class state{
public:
  int cost;
  int x1,y1,x2,y2;
  bool operator<(const state & a)const{
    if (y1 != a.y1)return y1 < a.y1;
    if (x1 != a.x1)return x1 < a.x1;
    if (x2 != a.x2)return x2 < a.x2;
    if (y2 != a.y2)return y2 < a.y2;
    return false;
  }
};

//bool vis[50][50][50][50];
bool m[100][100];

int dx[] ={0,0,1,-1};
int dy[] ={1,-1,0,0};
int dx2[]={0,0,-1,1};
int dy2[]={-1,1,0,0};

void bfs(int r,int c,int sy,int sx,int gy,int gx){
  set<state> S;
  queue<state> Q;
  S.insert((state){0,sy,sx,gy,gx});
  Q.push((state){0,sy,sx,gy,gx});
  while(!Q.empty()){
    state now = Q.front();Q.pop();
    if (now.cost >= 100)break;
    if (now.x1==now.x2 && now.y1==now.y2){
      cout << now.cost << endl;
      return;
    }

    rep(i,4){
      int nex =now.x1+dx[i] ,ney =now.y1+dy[i];
      int nnex=now.x2+dx2[i],nney=now.y2+dy2[i];
      if (nex ==-1||ney==-1 ||nex==c ||ney==r ||m[ney][nex]){
	nex=now.x1;
	ney=now.y1;
      }
      if (nnex==-1||nney==-1||nnex==c||nney==r||m[nney][nnex]){
	nnex=now.x2;
	nney=now.y2;
      }
      
      //      if (vis[ney][nex][nney][nnex]){
      //	continue;
      //      }
      //      vis[ney][nex][nney][nnex]=true;
      state next=(state){now.cost+1,ney,nex,nney,nnex};
      //Q.push((state){now.cost+1,ney,nex,nney,nnex});
      if (S.find(next) == S.end()){
	S.insert(next);
	Q.push(next);
      }
    }



  }
  cout <<"NA"<<endl;
}

main(){
  int c,r;
  while(cin>>c>>r&& c){
    int sy,sx,gy,gx;
    cin>>sx>>sy>>gx>>gy;
    sx--;sy--;gx--;gy--;
    rep(i,r){
      rep(j,c)cin>>m[i][j];
    }

    bfs(r,c,sy,sx,gy,gx);
  }
}

C++: #include <bits/stdc++.h>
using namespace std;

int table[51][51];

bool memo[51][51][51][51];

int main() {

    while(1){

        int w,h;

        //scanf(" %d %d",&w,&h);

        cin >> w >> h;

        if(w==0&&h==0) break;

        int tx,ty,kx,ky;

        //scanf(" %d %d %d %d",&tx,&ty,&kx,&ky);

        cin >> tx >> ty >> kx >> ky;

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

        for(int i=0;i<51;i++){
            for(int j=0;j<51;j++){
                table[i][j] = 1;
                for(int k=0;k<51;k++){
                    for(int r=0;r<51;r++){
                        memo[i][j][k][r] = false;
                    }
                }
            }
        }

        for(int i=0;i<h;i++){
            for(int j=0;j<w;j++){
                //scanf(" %d",&table[i][j]);
                cin >> table[i][j];
            }
        }
        
        if(table[v[0]][v[1]] == 1 || table[v[2]][v[3]] == 1){
            cout << "NA" << endl;
            continue;
        }

        /*printf("\n");

        for(int i=0;i<h;i++){
            for(int j=0;j<w;j++){
                printf("%d ",table[i][j]);
            }
            printf("\n");
        }*/

        //memset(memo,false,sizeof(memo));

        queue<vector<int> > q;

        vector<int> v(5);

        v[0] = tx; v[1] = ty; v[2] = kx; v[3] = ky; v[4] = 0;

        q.push(v);

        bool check = false;

        while(!q.empty()){

            v = q.front(); q.pop();

            if(v[4] >= 100){
                break;
            }

            /*if(v[0] >= w || v[1] >= h || v[2] >= w || v[3] >= h || v[0] < 0 || v[1] < 0 || v[2] < 0 || v[3] < 0 || table[v[0]][v[1]] == 1 || table[v[2]][v[3]] == 1){
                continue;
            }*/

            if(memo[v[0]][v[1]][v[2]][v[3]]){
                continue;
            }

            if(v[0] == v[2] && v[1] == v[3]){
                check = true;
                cout << v[4] << endl;
                break;
            }

            memo[v[0]][v[1]][v[2]][v[3]] = true;

            v[4]++;

            vector<int> before(5);

            for(int i=0;i<5;i++){
                before[i] = v[i];
            }

            v[0]--; v[2]++;

            if(v[0] > 0 && v[2] < w && table[v[0]][v[1]] == 0 && table[v[2]][v[3]] == 0) {
                q.push(v);
            }

            for(int i=0;i<5;i++){
                v[i] = before[i];
            }

            v[0]++; v[2]--;

            if(v[2] > 0 && v[0] < w && table[v[0]][v[1]] == 0 && table[v[2]][v[3]] == 0) {
                q.push(v);
            }

            for(int i=0;i<5;i++){
                v[i] = before[i];
            }

            v[1]++; v[3]--;

            if(v[3] > 0 && v[1] < h && table[v[0]][v[1]] == 0 && table[v[2]][v[3]] == 0) {
                q.push(v);
            }

            for(int i=0;i<5;i++){
                v[i] = before[i];
            }

            v[1]--; v[3]++;

            if(v[1] > 0 && v[3] < h && table[v[0]][v[1]] == 0 && table[v[2]][v[3]] == 0) {
                q.push(v);
            }

            /*if(v[0] >= w || v[1] >= h || v[2] >= w || v[3] >= h || v[0] < 0 || v[1] < 0 || v[2] < 0 || v[3] < 0 || table[v[0]][v[1]] == 1 || table[v[2]][v[3]] == 1){

            }else {
                q.push(v);
            }*/



        }

        if(!check){
            cout << "NA" << endl;
        }



    }

    return 0;
}