Go: package main

import (
	"bufio"
	"os"
	"strconv"
	"strings"
	"math"
	"fmt"
)

var scanner = bufio.NewScanner(os.Stdin)

func main() {
	dd := make([][]int, 1000)
	for i := range dd {
		dd[i] = make([]int, 1000)
	}
	num := make([]int,1000)
	inv := make([]int, 1001)
	x := make([]int, 1000)
	y := make([]int, 1000)
	vv := make([]int, 1000)
	nowt := make([]float64, 1000)
	rev := make([]int, 1000)
	for scanner.Scan() {
		n, _ := strconv.Atoi(scanner.Text())
		if n == 0 {
			break
		}
		for i := 0; i < n; i++ {
			scanner.Scan()
			buf1 := strings.Split(scanner.Text(), " ")
			num[i], _ = strconv.Atoi(buf1[0])
			x[i], _ = strconv.Atoi(buf1[1])
			y[i], _ = strconv.Atoi(buf1[2])
			inv[num[i]] = i
		}
		for i := 0; i < n; i++ {
			for j := 0; j < n; j++ {
				dd[i][j]=(x[i]-x[j])*(x[i]-x[j])+(y[i]-y[j])*(y[i]-y[j])
			}
		}
		scanner.Scan()
		m, _ := strconv.Atoi(scanner.Text())
		for i := 0; i < m; i++ {
			scanner.Scan()
			buf2 := strings.Split(scanner.Text(), " ")
			c, _ := strconv.Atoi(buf2[0])
			d, _ := strconv.Atoi(buf2[1])
			c = inv[c]
			d = inv[d]
			for j := 0; j < n; j++ {
				vv[j] = 0
				nowt[j]=999999999
				rev[j]=-1
			}
			nowt[c]=0
			for j := 0; j < n; j++ {
				M := 99999999
				at := 0
				for k := 0; k < n; k++ {
					if vv[k] == 0 && float64(M) > nowt[k] {
						M=int(nowt[k])
						at = k
					}
				}
				if M > 90000000 {
					break
				}
				vv[at]=1
				for k := 0; k < n; k++ {
					if vv[k] == 0 && dd[at][k]<=2500&&nowt[k]>nowt[at]+math.Sqrt(float64(dd[at][k])) {
						nowt[k]=nowt[at]+math.Sqrt(float64(dd[at][k]))
						rev[k] = at
					}
				}
			}
			if vv[d] == 0 {
				fmt.Println("NA")
			} else {
				stack := make([]int, 0)
				V := d
				for V != c {
					stack = append(stack, V)
					V = rev[V]
				}
				fmt.Print(num[c])
				for len(stack) > 0 {
					fmt.Printf(" %d", num[stack[len(stack)-1]])
					stack = stack[:len(stack)-1]
				}
				fmt.Println()
			}
		}
	}
}

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

#define dump(n) cout<<"# "<<#n<<'='<<(n)<<endl
#define repi(i,a,b) for(int i=int(a);i<int(b);i++)
#define peri(i,a,b) for(int i=int(b);i-->int(a);)
#define rep(i,n) repi(i,0,n)
#define per(i,n) peri(i,0,n)
#define all(c) begin(c),end(c)
#define mp make_pair
#define mt make_tuple

typedef unsigned int uint;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<double> vd;
typedef vector<vd> vvd;
typedef vector<string> vs;

const int INF=1e9;
const int MOD=1e9+7;
const double EPS=1e-9;

template<typename T1,typename T2>
ostream& operator<<(ostream& os,const pair<T1,T2>& p){
	return os<<'('<<p.first<<','<<p.second<<')';
}
template<typename T>
ostream& operator<<(ostream& os,const vector<T>& a){
	os<<'[';
	rep(i,a.size()) os<<(i?" ":"")<<a[i];
	return os<<']';
}

struct Edge{
	int src,dst;
	double weight;
	Edge(){}
	Edge(int s,int d,double w):src(s),dst(d),weight(w){}
};
typedef vector<vector<Edge>> Graph;
bool operator<(const Edge& a,const Edge& b){return a.weight<b.weight;}
bool operator>(const Edge& a,const Edge& b){return a.weight>b.weight;}

void Dijkstra(const Graph& g,int v,vd& dist,vi& prev)
{
	priority_queue<Edge,vector<Edge>,greater<Edge>> pq;
	pq.emplace(-1,v,0);
	while(pq.size()){
		Edge cur=pq.top(); pq.pop();
		if(dist[cur.dst]!=INF) continue;
		dist[cur.dst]=cur.weight;
		prev[cur.dst]=cur.src;
		for(Edge e:g[cur.dst])
			pq.emplace(e.src,e.dst,cur.weight+e.weight);
	}
}
void BuildPath(const vi& prev,int v,vi& path)
{
	for(int u=v;u!=-1;u=prev[u])
		path.push_back(u);
	reverse(all(path));
}

int main()
{
	for(int n;cin>>n && n;){
		vi bs(n),xs(n),ys(n);
		rep(i,n) cin>>bs[i]>>xs[i]>>ys[i];
		
		map<int,int> f;
		rep(i,n) f[bs[i]]=i;
		
		Graph g(n);
		rep(i,n) rep(j,n){
			int dx=xs[j]-xs[i],dy=ys[j]-ys[i];
			if(dx*dx+dy*dy<=50*50){
				double d=sqrt(dx*dx+dy*dy);
				g[i].emplace_back(i,j,d);
			}
		}
		
		vvd dists(n,vd(n,INF));
		vvi prevs(n,vi(n,-1));
		rep(i,n) Dijkstra(g,i,dists[i],prevs[i]);
		
		int m; cin>>m;
		rep(i,m){
			int u,v; cin>>u>>v; u=f[u],v=f[v];
			vi path; BuildPath(prevs[u],v,path);
			if(path.size()){
				rep(i,path.size())
					cout<<(i?" ":"")<<bs[path[i]];
				cout<<endl;
			}
			else
				cout<<"NA"<<endl;
		}
	}
}

C++: #include <iostream>
#include <cmath>
#define ROPE 50.0
#define NEXTD -30

using namespace std;
void reachable();
double dist(int,int);
int inv_in(int,int);

int index_[1000],x[1000],y[1000];
double dst[1000][1000];
int next[1000][1000];


int main(){
  //  int tmp;
  int b_num,root_num;
  //int index[1000],x[1000],y[1000];
  int s_index[1000],g_index[1000];
  //int map[1000];
  while(cin >> b_num && b_num!=0){
    //cin >> a;
    //cout << b_num << " Number of Buildings." <<endl;
    //cout << a << endl;


    //rîñÇÝÝA£vZ
    for(int i=0;i<b_num;i++){  
      //while(cin >>tmp){
      cin >> index_[i] >> x[i] >> y[i];
      //cout << index_[i] <<" " << x[i] <<" "<< y[i] << endl;
      for(int j=0;j<=i;j++){
	dst[i][j]= (dist(i,j) > ROPE) ? 10000000.0 : 100000+dist(i,j);
	dst[j][i]= dst[i][j];
	next[i][j] = (dist(i,j) > ROPE) ? NEXTD : j;
	next[j][i] = (dist(i,j) > ROPE) ? NEXTD : i;
      }
    }

    for(int k=0; k<b_num;k++){
      for(int i =0; i<b_num; i++){
	for(int j =0; j<b_num; j++){
	  if(dst[i][j] > dst[i][k] + dst[k][j]){
	    //cout << dst[i][j] << "Í" << dst[i][k] << "Æ" << dst[k][j] << "æèå«¢";
	    dst[i][j] = dst[i][k] + dst[k][j];
	    next[i][j] = next[i][k];
	    //cout << i << "ida" << j << "jda" << next[i][j] << "£XV" << endl;
	  }
	  //cout << i <<"ida" << j << "jda" << next[i][j] <<endl;
	}
      }
    }
    
    cin >> root_num;
    for(int i=0;i < root_num;i++){
      int S,G;
      cin >> s_index[i] >> g_index[i];
      S=inv_in(b_num,s_index[i]);
      G=inv_in(b_num,g_index[i]);
      //cout << s_index[i] <<" " << g_index[i] <<" Start and Goal index"<< endl;
      //cout << inv_in(b_num,s_index[i]) <<" " << inv_in(b_num,g_index[i]) 
      //	   <<" Start and Goal num"<< endl;
      
      //cout << "S" << S << "G" << G << endl;
     
      
      if(next[i][G]!=NEXTD){
	for(int j=S;j!=G;j=next[j][G]){
	  cout << index_[j] << ' ' ;
	}
	cout << index_[G] << endl;
      }
      else{
	cout << "NA" << endl;
      }    
    }
    
    
    /*
    for(int i=0;i<b_num;i++){
      for(int k=0;k<b_num;k++){
	cout << next[i][k] << " -> " << i << "Æ" << k << "ÆÌÔÌÌs«æ" << endl; 
	//	dst[i][j]
      }
      cout << endl;
    }
    */
  }
  
}

double dist(int i,int j){
  double dis;
  dis = pow(pow(double(x[i]-x[j]),2.0)+pow(double(y[i]-y[j]),2.0),0.5);
  return dis;
}

int inv_in(int b_num,int b_ind){
  int inv;
  for(int j=0;j<b_num;j++){
    if(index_[j]==b_ind){
      inv = j;
      break;
    }
  }
  return inv;
}