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 := &Status{}
		*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<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int> pll;
typedef pair<pll,pll> P;
int main(){
  int dx[5]={1,-1,0,0},dy[5]={0,0,1,-1},dw[5]={-1,1,0,0},dz[5]={0,0,-1,1};
  while(1){
    int w,h;
    int ans=100;
    cin >> h >> w;
    if(w==0 && h==0){
      return 0;
    }
    int i,j,k,l,tx,ty,kx,ky,a[55][55],b[55][55][55][55];
    cin >> tx >> ty >> kx >> ky;
    for(i=0;i<=w+1;i++){
      for(j=0;j<=h+1;j++){
        a[i][j]=1;
      }
    }
    for(i=1;i<=w;i++){
      for(j=1;j<=h;j++){
        scanf("%d",&a[i][j]);
      }
    }
    for(i=1;i<=w;i++){
      for(j=1;j<=h;j++){
        for(k=1;k<=w;k++){
          for(l=1;l<=h;l++){
            b[i][j][k][l]=100;
          }
        }
      }
    }
    b[ty][tx][ky][kx]=0;
    queue<P> que;
    que.push(make_pair(pll(ty,tx),pll(ky,kx)));
    while(!que.empty()){
      P p=que.front();
      que.pop();
      if(p.first.first==p.second.first && p.first.second==p.second.second && ans>b[p.first.first][p.first.second][p.second.first][p.second.second]){
        ans=b[p.first.first][p.first.second][p.second.first][p.second.second];
      }
      if(b[p.first.first][p.first.second][p.second.first][p.second.second]>=ans){
        continue;
      }
      for(i=0;i<4;i++){
        if(a[p.first.first+dx[i]][p.first.second+dy[i]]==1 && a[p.second.first+dw[i]][p.second.second+dz[i]]==0 && b[p.first.first][p.first.second][p.second.first+dw[i]][p.second.second+dz[i]]>b[p.first.first][p.first.second][p.second.first][p.second.second]+1){
          b[p.first.first][p.first.second][p.second.first+dw[i]][p.second.second+dz[i]]=b[p.first.first][p.first.second][p.second.first][p.second.second]+1;
          que.push(make_pair(pll(p.first.first,p.first.second),pll(p.second.first+dw[i],p.second.second+dz[i])));
        }
        else if(a[p.first.first+dx[i]][p.first.second+dy[i]]==0 && a[p.second.first+dw[i]][p.second.second+dz[i]]==1 && b[p.first.first+dx[i]][p.first.second+dy[i]][p.second.first][p.second.second]>b[p.first.first][p.first.second][p.second.first][p.second.second]+1){
          b[p.first.first+dx[i]][p.first.second+dy[i]][p.second.first][p.second.second]=b[p.first.first][p.first.second][p.second.first][p.second.second]+1;
          que.push(make_pair(pll(p.first.first+dx[i],p.first.second+dy[i]),pll(p.second.first,p.second.second)));
        }
        else if(a[p.first.first+dx[i]][p.first.second+dy[i]]==0 && a[p.second.first+dw[i]][p.second.second+dz[i]]==0 && b[p.first.first+dx[i]][p.first.second+dy[i]][p.second.first+dw[i]][p.second.second+dz[i]]>b[p.first.first][p.first.second][p.second.first][p.second.second]+1){
          b[p.first.first+dx[i]][p.first.second+dy[i]][p.second.first+dw[i]][p.second.second+dz[i]]=b[p.first.first][p.first.second][p.second.first][p.second.second]+1;
          que.push(make_pair(pll(p.first.first+dx[i],p.first.second+dy[i]),pll(p.second.first+dw[i],p.second.second+dz[i])));
        }
      }
    }
    if(ans==100){
      cout << "NA" << endl;
    }
    else{
      cout << ans << endl;
    }
  }
}

C++: #include<iostream>
#include<algorithm>
using namespace std;
int h,w;
int map[100][100];
int qtx[100000],qty[100000],qkx[100000],qky[100000];
int ql[100000];
int tail,head;
int ans;
int dx[4]={0,1,0,-1},dy[4]={1,0,-1,0};
bool vis[60][60][60][60];
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;
	for(int i=0;i<60;i++){
		for(int j=0;j<60;j++){
			for(int k=0;k<60;k++){
				for(int r=0;r<60;r++){
					vis[i][j][k][r]=false;
				}
			}
		}
	}
	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;
		if(!vis[qtx[head]][qty[head]][qkx[head]][qky[head]]){
		vis[qtx[head]][qty[head]][qkx[head]][qky[head]]=true;
		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;
}