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 <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++){
      cin >> s_index[i] >> g_index[i];
      int S=inv_in(b_num,s_index[i]);
      int 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;
}

C++: #include<cstdio>
#include<cstdlib>
#include<cmath>
#include<cstring>
#include<cctype>
#include<complex>
#include<iostream>
#include<sstream>
#include<algorithm>
#include<functional>
#include<vector>
#include<string>
#include<stack>
#include<queue>
#include<map>

using namespace std;
const int dx[] = {1,0,-1,0},dy[] = {0,1,0,-1};
#define INF 10000000
#define rep(i,j) for(int i=0;i<(j);++i)
#define reps(i,j,k) for(int i=j;i<k;++i)
typedef long long ll;
typedef unsigned long long ull;

double cost[1024][1024];
int d[1024];
bool used[1024];
int prev[1024];
int V;

void dijkstra(int s){
	fill(d,d+V,INF);
	fill(used,used+V,false);
	fill(prev,prev+V,-1);
	d[s] = 0;
	while(true){
		int v = -1;
		rep(i,V)if(!used[i] && (v == -1 || d[i] < d[v]))v = i;
		if(v == -1)break;
		used[v] = true;
		rep(i,V){
			if(d[i] > d[v] + cost[v][i]){
				d[i] = d[v] + cost[v][i];
				prev[i] = v;
			}
		}
	}
	return ;
}

vector<int> get_path(int t){
	vector<int> path;
	for(; t != -1; t = prev[t])path.push_back(t);
	reverse(path.begin(),path.end());
	return path;
}

int main(){
	int n;
	while(scanf("%d",&n),n){
		rep(i,1024)rep(j,1024)cost[i][j] = INF;
		int num[12800]={0},x[12800]={0},y[12800]={0};
		int ma = 0;
		rep(i,n){
			scanf("%d%d%d",&num[i],&x[i],&y[i]);
			num[i]--;
		}
		rep(i,n){
			reps(j,i+1,n){
				double dis = sqrt(((x[i]-x[j])*(x[i]-x[j]))+((y[i]-y[j])*(y[i]-y[j])));
				cost[num[i]][num[j]] = (dis > 50) ? INF : dis;
				cost[num[j]][num[i]] = (dis > 50) ? INF : dis;
			}
		}
		V = n;
		int m;
		scanf("%d",&m);
		rep(i,m){
			vector<int> ans;
			int from,to;
			scanf("%d%d",&from,&to);
			from--;to--;
			dijkstra(from);
			ans = get_path(to);
			int len = ans.size();
			if(d[to] == INF)puts("NA");
			else{
				rep(j,len-1)printf("%d ",ans[j]+1);
				printf("%d\n",ans[len-1]+1);
			}			
		}
	}
	return 0;
}