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<algorithm>
#include<map>
#include<set>
#include<utility>
#include<vector>
#include<cmath>
#include<cstdio>
#define loop(i,a,b) for(int i=a;i<b;i++) 
#define rep(i,a) loop(i,0,a)
#define pb push_back
#define mp make_pair
#define it ::iterator
#define all(in) in.begin(),in.end()
const double PI=acos(-1);
const double ESP=1e-10;
using namespace std;
int main(){
  long long int in;
  while(cin>>in,in){
    string ans="";
    long long int t=1;
    int i=0;
    while(in!=0){
      i++;
      t*=10;
      if(i%2){
	int co=0;
	while((double)in/t!=in/t){co++;in-=t/10;}
	ans=(char)(co+'0')+ans;
      }else{
	int co=0;
	while((double)in/t!=in/t){co++;in+=t/10;}
	ans=(char)(co+'0')+ans;
      }
      //cout<<in<<endl;
    }
    cout<<ans<<endl;
  }


}

C++: #include<stdio.h>
#include<algorithm>
#include<queue>
using namespace std;
int m[50][50];
int dx[]={1,-1,0,0};
int dy[]={0,0,1,-1};
int bfs[50][50][50][50];
struct wolf{
	int a,b,c,d;
	wolf(int A,int B,int C,int D){
		a=A;
		b=B;
		c=C;
		d=D;
	}
};
int main(){
	int a,b;
	while(scanf("%d%d",&a,&b),a+b){
		int r1,r2,c1,c2;
		scanf("%d%d%d%d",&r1,&c1,&r2,&c2);
		for(int i=0;i<b;i++)
			for(int j=0;j<a;j++)
				scanf("%d",&m[i][j]);
		int inf=999999999;
		for(int i=0;i<b;i++)
			for(int j=0;j<a;j++)
				for(int k=0;k<b;k++)
					for(int l=0;l<a;l++)
						bfs[i][j][k][l]=inf;
		r1--;c1--;r2--;c2--;
		bfs[r1][c1][r2][c2]=0;
		queue<wolf> Q;
		Q.push(wolf(r1,c1,r2,c2));
		while(Q.size()){
			wolf at=Q.front();
			Q.pop();
			if(bfs[at.a][at.b][at.c][at.d]==100)continue;
			for(int i=0;i<4;i++){
				int s1=at.a+dx[i];
				int t1=at.b+dy[i];
				int s2=at.c-dx[i];
				int t2=at.d-dy[i];
				if(s1<0||s1>=b||m[s1][t1])s1-=dx[i];
				if(t1<0||t1>=a||m[s1][t1])t1-=dy[i];
				if(s2<0||s2>=b||m[s2][t2])s2+=dx[i];
				if(t2<0||t2>=a||m[s2][t2])t2+=dy[i];
				if(bfs[s1][t1][s2][t2]==inf){
					bfs[s1][t1][s2][t2]=bfs[at.a][at.b][at.c][at.d]+1;
					Q.push(wolf(s1,t1,s2,t2));
				}
			}
		}
		int ret=inf;
		for(int i=0;i<b;i++)for(int j=0;j<a;j++)ret=min(ret,bfs[i][j][i][j]);if(ret==inf)printf("NA\n");else printf("%d\n",ret);
	}
}

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;
    }
  }
}