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++: // AOJ 0155
// URL: http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=0155

#include <iostream>
#include <sstream>
#include <map>
#include <queue>
#include <cmath>
#include <algorithm>
using namespace std;

typedef pair <int, vector <int> > PIV;
typedef pair <double, PIV > PDV;
typedef priority_queue <PDV, vector<PDV>, greater <PDV> > QUEUE;

const double eps = 1e-9;
const int size = 1001;
const string NA = "NA";
int n, m;
int b[size], x[size], y[size];
map <int, int> cor; // number to index
bool path[size][size];
double cost[size][size];
double min_cost[size];
int con[size][size]; // connect
int concnt[size]; // connect count

double get_distance( int x1, int y1, int x2, int y2 )
{
    double x = ( x2 - x1 ), y = ( y2 - y1 );
    return fabs( sqrt( x * x + y * y ) );
}

// dijkstra
string solve( int s_, int g_ )
{
    int start = cor[s_], goal = cor[g_];
    if ( !path[start][goal] ) return NA;

    // init
    ostringstream os;
    QUEUE Q;
    PDV start_node( 0.0, PIV( start , vector<int>() ) );
    Q.push( start_node );
    min_cost[start] = 0.0;
    bool used[size] = {false};

    // proc
    while ( !Q.empty() ) {
        PDV node = Q.top();
        Q.pop();

        // proc init
        double c = node.first;
        int ind = node.second.first;
        int number = b[ind];
        vector <int> route = node.second.second;
        route.push_back( number );
        used[ind] = true;

        // cout << ind << "(" << number << "), c=" << c << ", route.size=" << route.size() << endl;

        // goal, output
        if ( number == g_ ) {
            for ( vector <int> ::iterator it = route.begin(); it != route.end(); it++ ) {
                os << *it;
                if ( it + 1 != route.end() ) os << " ";
            }
            return os.str();
        }

        // move
        for ( int i = 0; i < concnt[ind]; i++ ) {
            int next_ind = con[ind][i];
            if ( used[next_ind] ) continue;
            int next_number = b[next_ind];
            double next_c = c + cost[ind][next_ind];
            if ( next_c < min_cost[next_ind] ) {
                min_cost[next_ind] = next_c;
                PDV next_node( next_c, PIV( next_ind, route ) );
                Q.push( next_node );
            }
        }
    }

    return NA;
}

int main( void )
{
    while ( cin >> n && n ) {
        // init
        cor.clear();
        for ( int i = 0; i < n; i++ ) {
            min_cost[i] = (double)(1<<24);
            for ( int j = 0; j < n; j++ ) {
                path[i][j] = false;
            }
            concnt[i] = 0;
        }

        // input
        for ( int i = 0; i < n; i++ ) {
            cin >> b[i] >> x[i] >> y[i];
            cor[b[i]] = i;
        }

        for ( int i = 0; i < n; i++ ) {
            for ( int j = 0; j < n; j++ ) {
                if ( i == j ) continue;
                cost[i][j] = get_distance( x[i], y[i], x[j], y[j] );
            }
        }

        // proc
        for ( int i = 0; i < n; i++ ) {
            for ( int j = 0; j < n; j++ ) {
                if ( i == j ) continue;
                if ( cost[i][j] < 50.0 + eps ) {
                    path[i][j] = true;
                    con[i][concnt[i]++] = j;
                }
            }
        }

        // floyd-warshall
        for ( int k = 0; k < n; k++ ) {
            for ( int i = 0; i < n; i++ ) {
                for ( int j = 0; j < n; j++ ) {
                    if ( i == k || k == j || j == i ) continue;
                    if ( path[i][k] && path[k][j] ) path[i][j] = true;
                }
            }
        }

        // query
        cin >> m;
        for ( int i = 0; i < m; i++ ) {
            int s, t;
            cin >> s >> t;
            cout << solve( s, t ) << endl;
        }
    }
    return 0;
}

C++: #include<iostream>
#include<cmath>
#include<vector>
#include<cstdlib>
#include<algorithm>
#define INF 100000000

using namespace std;

void init(int);
int find(int);
void unite(int,int);
bool same(int,int);
void dijkstra(int);
vector<int>get_path(int);

int par[1001],rank[1001];
int V,prev[1001];
double cost[1001][1001],d[1001];
bool used[1001];

int main(void){

  int b[1001],m,s[1001],g[1001];
  double x[1001],y[1001];
  while(cin >> V,V){
    for(int i=0;i<V;i++){
      cin >> b[i] >> x[i] >> y[i];
    }

    cin >> m;
    for(int i=0;i<m;i++){
      cin>> s[i] >> g[i];
    }

    init(V);

    for(int i=0;i<=V;i++)
      for(int j=0;j<=V;j++)
	cost[i][j]=INF;

    for(int i=0;i<V;i++){
      for(int j=0;j<V;j++){
	if(i!=j){
	  double a=sqrt(pow(x[i]-x[j],2)+pow(y[i]-y[j],2));
	  if(a<=50.){
	    cost[b[i]][b[j]]=cost[b[j]][b[i]]=a;
	    unite(b[i],b[j]);
	  }
	}
      }
    }

    for(int i=0;i<m;i++){
      if(!same(s[i],g[i])){
	cout << "NA" << endl;
      }
      else {
	dijkstra(s[i]);
	vector<int>p=get_path(g[i]);
	for(int j=0;j<p.size();j++){
	  cout << p[j];
	  if(j!=p.size()-1)cout <<" ";
	  else cout << endl;
	}
      }
      
    }

  }

  return 0;
}

void init(int n){
  for(int i=0;i<n;i++){
    par[i]=i;
    rank[i]=0;
  }
}

int find(int x){
  if(par[x]==x)return x;
  else return par[x]=find(par[x]);
}

void unite(int x,int y){
  x=find(x);
  y=find(y);
  if(x==y)return;

  if(rank[x]<rank[y])par[x]=y;
  else{
    par[y]=x;
    if(rank[x]==rank[y])rank[x]++;
  }
}

bool same(int x,int y){
  return find(x)==find(y);
}

void dijkstra(int s){
  fill(d,d+V+1,INF);
  fill(used,used+V+1,false);
  fill(prev,prev+V+1,-1);
  d[s]=0;

  while(true){
    int v=-1;
    for(int u=1;u<=V;u++){
      if(!used[u]&&(v==-1||d[u]<d[v]))v=u;
    }

    if(v==-1)break;
    used[v]=true;

    for(int u=1;u<=V;u++){
      if(d[u]>d[v]+cost[v][u]){
	d[u]=d[v]+cost[v][u];
	prev[u]=v;
      }
    }
  }
}

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;
}