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<string>
#include<map>
#include<queue>

#define rep(i,n) for(int i=0;i<int(n);i++)
#define sint(i) scanf("%d",&i);
#define sintt(i,j) scanf("%d%d",&i,&j);
using namespace std;

int xx,yy;

class Q{
	public:
	int bx,by,bbx,bby;
	int dep;
	Q(int bx,int by,int bbx,int bby,int dep):
	bx(bx),by(by),bbx(bbx),bby(bby),dep(dep){}
};

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

int masu[51][51];
int memo[51][51][51][51];

int search(int bx,int by,int bbx,int bby){
	
	queue<Q> hako;
	
	hako.push(Q(bx,by,bbx,bby,0));
	
	while(1){
		if(hako.empty()==1){
			break;
		}
		
		Q u=hako.front();
		hako.pop();
		if(u.bx<=0 || u.by<=0 || u.bx>xx || u.by>yy || masu[u.bx][u.by]==1){
			continue;
		}
		if(u.bbx<=0 || u.bby<=0 || u.bbx>xx || u.bby>yy || masu[u.bbx][u.bby]==1){
			continue;
		}
		
		if(memo[u.bx][u.by][u.bbx][u.bby]==1){
			continue;
		}else{
			memo[u.bx][u.by][u.bbx][u.bby]=1;
		}
		if(u.bx==u.bbx && u.by==u.bby){
			return u.dep;
		}
		
		
		rep(i,4){
			hako.push(Q(u.bx+dx[i],u.by+dy[i],u.bbx+dx[(i+2)%4],u.bby+dy[(i+2)%4],u.dep+1));
		}
	}
	return -1;
}

int main(){
	while(1){
		sintt(xx,yy);
		
		if(xx==0){
			break;
		}
		int bx,by,bbx,bby;
		sintt(bx,by);
		sintt(bbx,bby);
		
		rep(i,51)rep(j,51)rep(k,51)rep(p,51){
		memo[i][j][k][p]=0;
		}
		
		rep(i,yy){
			rep(j,xx){
				sint(masu[j+1][i+1]);
			}
		}
		
		int ans=search(bx,by,bbx,bby);
		if(ans==-1){
			puts("NA");
		}else{
			printf("%d\n",ans);
		}
	}
}

C++: #include<iostream>
#include<algorithm>
using namespace std;
int h,w;
int map[100][100];
int qtx[1000000],qty[1000000],qkx[1000000],qky[1000000];
int ql[1000000];
int tail,head;
int ans;
int dx[4]={0,1,0,-1},dy[4]={1,0,-1,0};
bool bend;
void BFS(int tx,int ty,int kx,int ky,int len){
	if(len==100)return;
	if(tx==kx&&ty==ky){
		ans=len;
		bend=true;
		return;
	}
	for(int i=0;i<4;i++){
		bool mt=false,mk=false;
		if(tx+dx[i]>=0&&tx+dx[i]<w&&ty+dy[i]>=0&&ty+dy[i]<h){
			if(map[ty+dy[i]][tx+dx[i]]==0){
				mt=true;
			}
		}
		if(kx-dx[i]>=0&&kx-dx[i]<w&&ky-dy[i]>=0&&ky-dy[i]<h){
			if(map[ky-dy[i]][kx-dx[i]]==0){
				mk=true;
			}
		}
		qtx[tail]=tx+mt*dx[i],qty[tail]=ty+mt*dy[i];
		qkx[tail]=kx-mk*dx[i],qky[tail]=ky-mk*dy[i];
		ql[tail]=len+1;
		tail++;
	}
}
int main(){
	while(true){
	cin>>w>>h;
	if(w==0&&h==0)break;
	int tx,ty,kx,ky;
	cin>>tx>>ty>>kx>>ky;
	tx--,ty--,kx--,ky--;
	for(int i=0;i<h;i++){
		for(int j=0;j<w;j++){
			cin>>map[i][j];
		}
	}
	ans=869121;
	qtx[0]=tx,qty[0]=ty,qkx[0]=kx,qky[0]=ky;
	ql[0]=0;
	tail=1,head=0;
	bend=false;
	while(true){
		if(tail==head)break;
		BFS(qtx[head],qty[head],qkx[head],qky[head],ql[head]);
		if(bend)break;
		head++;
	}
	if(ans==869121)cout<<"NA"<<endl;
	else cout<<ans<<endl;
	}
	return 0;
}

C++: #include<iostream>
#include<queue>
using namespace std;

const int INF = 100000000;

class Point{
public:
  int x;
  int y;
  int x2;
  int y2;
};

int main(){
  int N,M;
  cin >> N >> M;
  char F[102][102];
  for(int y=0; y<=N+1; y++){
    for(int x=0; x<=M+1; x++){
      F[y][x] = 1;
    }
  }

  int tx,ty;
  int kx,ky;
  cin >> tx >> ty;
  cin >> kx >> ky;

  for(int y=1; y<=N; y++){
    for(int x=1; x<=M; x++){
      cin >> F[y][x];
    }
  }

  int D[102][102];
  for(int y=1; y<=N; y++){
    for(int x=1; x<=M; x++){
      D[y][x] = INF;
    }
  }

  queue<Point> que;

  Point p;
  p.x = tx; p.y = ty;
  p.x2 = kx; p.y2 = ky;
  que.push(p);
  D[p.y][p.x] = 0;

  while(!que.empty()){
    p = que.front(); que.pop();

    if(p.x==p.x2 && p.y==p.y2){
      cout << D[p.y][p.x] << endl;
      cout << p.x << p.y << endl;
      break;
    }

    if(F[p.y-1][p.x]!= 1 && F[p.y2+1][p.x2]!= 1 && D[p.y-1][p.x]==INF){
      Point q;
      q.x = p.x; q.y = p.y-1;
      q.x2 = p.x2; q.y2 = p.y2+1;

      if(F[q.x][q.y]==1){
        q.y = p.y;
      }else if(F[q.x2][q.y2]==1){
        q.y2 = p.y2;
      }

      que.push(q);
      D[q.y][q.x] = D[p.y][p.x]+1;
    }
    if(F[p.y+1][p.x]!=1 && F[p.y2-1][p.x2]!=1 && D[p.y+1][p.x]==INF){
      Point q;
      q.x = p.x; q.y = p.y+1;
      q.x2 = p.x2; q.y2 = p.y2-1;

      if(F[q.x][q.y]==1){
        q.y = p.y;
      }else if(F[q.x2][q.y2]==1){
        q.y2 = p.y2;
      }

      que.push(q);
      D[q.y][q.x] = D[p.y][p.x]+1;
    }
    if(F[p.y][p.x-1]!=1 && F[p.y2][p.x2+1]!=1 && D[p.y][p.x-1]==INF){
      Point q;
      q.x = p.x-1; q.y = p.y;
      q.x2 = p.x2+1; q.y2 = p.y2;

      if(F[q.x][q.y]==1){
        q.x = p.x;
      }else if(F[q.x2][q.y2]==1){
        q.x2 = p.x2;
      }

      que.push(q);
      D[q.y][q.x] = D[p.y][p.x]+1;
    }
    if(F[p.y][p.x+1]!=1 && F[p.y2][p.x2-1]!=1 && D[p.y][p.x+1]==INF){
      Point q;
      q.x = p.x+1; q.y = p.y;
      q.x2 = p.x2-1; q.y2 = p.y2;

      if(F[q.x][q.y]==1){
        q.x = p.x;
      }else if(F[q.x2][q.y2]==1){
        q.x2 = p.x2;
      }

      que.push(q);
      D[q.y][q.x] = D[p.y][p.x]+1;
    }

  }

  return 0;
}