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

typedef pair <double, int> PDI;
typedef pair <PDI, vector <int> > PPV;
typedef priority_queue <PPV, vector <PPV>, greater <PPV> > 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;
bool path[size][size];
double cost[size][size];
double min_cost[size][size];
int con[size][size]; // connect
int concnt[size]; // connect count

// <=
bool big_equal( double a, double b )
{
    if ( a < b + eps ) return true;
    return fabs( a - b ) < eps;
}

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

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

    // init
    QUEUE Q;
    PPV start_node( PDI( 0.0, start ), vector<int>() );
    Q.push( start_node );
    vector <int> min_route;
    double minc = (double)(1<<24);

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

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

        // goal
        if ( number == g_ ) {
            if ( !( c > minc ) ) {
                min_route = route;
                minc = c;
            }
        }

        for ( int i = 0; i < concnt[ind]; i++ ) {
            int next_ind = con[ind][i];
            if ( count( route.begin(), route.end(), b[next_ind] ) ) continue;
            double next_c = c + cost[ind][next_ind];
            if ( !( min_cost[ind][next_ind] < next_c ) ) {
                min_cost[ind][next_ind] = next_c;
                PPV next_node( PDI( next_c, next_ind ), route );
                Q.push( next_node );
            }
        }
    }

    ostringstream os;
    for ( vector <int> ::iterator it = min_route.begin(); it != min_route.end(); it++ ) {
        os << *it;
        if ( it + 1 != min_route.end() ) os << " ";
    }

    return os.str();
}

int main( void )
{
    while ( cin >> n && n ) {
        // init
        cor.clear();
        for ( int i = 0; i < n; i++ ) {
            for ( int j = 0; j < n; j++ ) {
                path[i][j] = false;
                min_cost[i][j] = (double)(1<<24);
            }
            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] = getDistance( 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 ( big_equal( cost[i][j], 50.0 ) ) {
                    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 <queue>
#include <vector>
#include <cmath>
#include <algorithm>
#define INF 100000000
using namespace std;
typedef pair<double,int> P;
struct edge {
  int to;
  double cost;
};
int n,m;
int b[1000],x[1000],y[1000];
double d[1000];
vector<edge> V[1000];
int prev[1000];

double dist(int from, int to) {
  return sqrt( (x[to] - x[from])*(x[to] - x[from]) + (y[to] - y[from])*(y[to] - y[from]) );
}

void dijkstra(int s) {
  priority_queue <P, vector<P>, greater<P> > que;
  for(int i=0;i<n;i++) {
    d[i] = INF;
  }
  d[s] = 0;
  prev[s] = INF;
  que.push(P(0,s));

  while(!que.empty()) {
    P p = que.top();que.pop();
    int v = p.second;
    if(d[v] < p.first) continue;
    for(int i=0;i<V[v].size();i++) {
      edge e = V[v][i];
      if(d[e.to] > d[v] + e.cost) {
	d[e.to] = d[v] + e.cost;
	prev[e.to] = v;
	que.push(P(d[e.to],e.to));
      }
    }
  }
}

int main() {

  while(cin >> n) {
    if(n==0) break;
    for(int i=0;i<n;i++) {
      cin >> b[i] >> x[i] >> y[i];
    }

    for(int i=0;i<n;i++) {
      for(int j=i+1;j<n;j++) {
	double r = dist(i,j);
	if(r <= 50.0) {
	  edge temp;
	  temp.to = j;
	  temp.cost = r;
	  V[i].push_back(temp);
	  temp.to = i;
	  V[j].push_back(temp);
	}
      }
    }
    cin >> m;
    for(int i=0;i<m;i++) {
      int s,g,ps,pg;
      cin >> ps >> pg;
      for(int i=0;i<n;i++) {
	if(b[i] == ps) s = i;
	else if(b[i] == pg) g = i;
      }
      dijkstra(s);
      if(d[g] != INF) {
	int t = g;
	vector<int> path;
	for(;t != s;t = prev[t]) {
	  path.push_back(t);
	}
	path.push_back(s);
	reverse(path.begin(),path.end());
	for(int i=0;i<path.size();i++) {
	  cout << (i==0 ? "":" ") << b[path[i]];
	}
	cout << endl;
	path.clear();
      }
      else
	cout << "NA" << endl;
    }
    for(int i=0;i<n;i++) {
      V[i].clear();
    }
  }
}