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>
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;
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];
int concnt[size];

// <=
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_ )
{
    int start = cor[s_], goal = cor[g_];
    if ( !path[start][goal] ) return "NA";

    // init
    ostringstream os;
    QUEUE Q;
    PPV start_node( PDI( 0.0, start ), vector<int>() );
    Q.push( start_node );

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

        for ( int i = 0; i < concnt[ind]; i++ ) {
            int next_ind = con[ind][i];
            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 );
            }
        }
    }

    return os.str();
}

int main( void )
{
    while ( cin >> n && n ) {
        // init
        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] = path[j][i] = true;
                    con[i][concnt[i]] = j;
                    concnt[i]++;
                    con[j][concnt[j]] = i;
                    concnt[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] ) continue;
                    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<cstdio>
#include<iostream>
#include<vector>
#include<algorithm>
#include<queue>
#include<stack>
#include<cmath>
using namespace std;

const double EPS = 1e-6;

struct Building{
	int x, y;
	Building(){
		x = -1; y = -1;
	}
};

struct Edge{
	int to;
	double cost;
	Edge(){}
	Edge(const int &_to, const double &_cost){
		to = _to; cost = _cost;
	}
};

struct Data{
	int n;
	double cost;
	Data(){}
	Data(const int &_n, const double &_cost){
		n = _n; cost = _cost;
	}
	bool operator < (const Data &a) const{
		return cost > a.cost;
	}
};

double GetDistance(const Building &b1, const Building &b2){
	double dx = b1.x - b2.x, dy = b1.y - b2.y;
	return sqrt(dx*dx + dy*dy);
}

vector<Edge> e[1000];
Building v[1000];
priority_queue<Data> pq;

int main(){
	int N, M, B, S, G;

	while(cin >> N, N){
		for(int i = 0; i < 1000; i++) e[i].clear();

		for(int i = 0; i < N; i++){
			cin >> B; B--;
			cin >> v[B].x >> v[B].y;
		}

		for(int i = 0; i < N; i++){
			for(int j = i+1; j < N; j++){
				if(v[i].x == -1 || v[j].x == -1 || i == j) continue;
				double dist = GetDistance(v[i], v[j]);
				if(dist <= 50){
					e[i].push_back( Edge(j, dist) );
					e[j].push_back( Edge(i, dist) );
				}
			}
		}

		cin >> M;
		for(int j = 0; j < M; j++){
			cin >> S >> G; S--; G--;

			Data pq_top;
			pq.push( Data(S, 0) );
			double memo[1000];
			fill_n(memo, 1000, -1);
			bool na = true;

			while( !pq.empty() ){
				pq_top = pq.top(); pq.pop();
			
				if(memo[pq_top.n] > -0.5) continue;
				memo[pq_top.n] = pq_top.cost;
				if(pq_top.n == G){
					na = false; break;
				}

				for(int i = 0; i < e[pq_top.n].size(); i++){
					pq.push( Data( e[pq_top.n][i].to, pq_top.cost + e[pq_top.n][i].cost ) );
				}
			}
			while( !pq.empty() ) pq.pop();

			if(na){
				puts("NA"); continue;
			}

			stack<int> ans;
			while(true){
				ans.push(G);
				if(G == S) break;
				for(int i = 0; i < e[G].size(); i++){
					if( abs(memo[G] - memo[ e[G][i].to ] - e[G][i].cost) < EPS){
						G = e[G][i].to; break;
					}
				}
			}
		
			printf("%d", ans.top()+1 ); ans.pop();
			while( !ans.empty() ){
				printf(" %d", ans.top()+1 ); ans.pop();
			}puts("");
		}
	}
	return 0;
}