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 <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; // number to index
map <int, int> T; // index to number;
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 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 );
    min_cost[start] = 0.0;

    // 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];
            int next_number = b[next_ind];
            if ( find( route.begin(), route.end(), next_number ) != route.end() ) continue;
            double next_c = c + cost[ind][next_ind];
            if ( next_c < min_cost[next_ind] ) {
                min_cost[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
        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 ) {
                    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<cstdio>
#include<string>
#include<vector>
#include<algorithm>
#include<unordered_map>
#include<queue>
#include<functional>
#define P pair<double,int>//cost to
using namespace std;

int x[100], y[100], k[100];
unordered_map<int, int>U;
vector<P>rinsetu[100];
double mincost[100];
int Prev[100];
vector<int>V;
int s, g;
void saiki(int a) {
	V.push_back(a);
	if (Prev[a] != s) {
		saiki(Prev[a]);
	}
}
int main() {
	int a;
	while (cin >> a, a) {
		U.clear();
		for (int b = 0; b < a; b++) {
			int c;
			scanf("%d%d%d",&c, &x[b], &y[b]);
			U[c] = b;
			k[b] = c;
			rinsetu[b].clear();
		}
		for (int b = 0; b < a; b++) {
			for (int c = b + 1; c < a; c++) {
				double d = pow(x[b] - x[c], 2)+pow(y[b] - y[c], 2);
				d = sqrt(d);
				if (d <= 50) {
					rinsetu[b].push_back(P(d, c));
					rinsetu[c].push_back(P(d, b));
				}
			}
		}
		int b; cin >> b;
		for (int c = 0; c < b; c++) {
		    scanf("%d%d", &s, &g);
			s = U[s]; g = U[g];
			fill(mincost, mincost + a, 1 << 29);
			mincost[s] = 0;
			priority_queue<P, vector<P>, greater<P>>Q;
			Q.push(P(0,s));
			while (Q.size()) {
				P t = Q.top(); Q.pop();
				if (mincost[t.second] > t.first)continue;
				for (P i : rinsetu[t.second]) {
					if (mincost[i.second] > t.first + i.first) {
						mincost[i.second] = t.first + i.first;
						Q.push(P(mincost[i.second],i.second));
						Prev[i.second] = t.second;
					}
				}
			}
			if (mincost[g] == 1 << 29) { puts("NA"); }
			else {
				V.clear();
				saiki(g);
				V.push_back(s);
				reverse(V.begin(), V.end());
				for (int i = 0; i < V.size(); i++) {
					if (i)cout << " ";
					cout << k[V[i]];
				}
				cout << endl;
			}
		}
	}
}