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 <iomanip>
#include <cstdio>
#include <string>
#include <cstring>
#include <deque>
#include <list>
#include <queue>
#include <stack>
#include <vector>
#include <utility>
#include <algorithm>
#include <map>
#include <set>
#include <complex>
#include <cmath>
#include <limits>
#include <cfloat>
#include <climits>
#include <ctime>
#include <cassert>
#include <numeric>
#include <fstream>
#include <functional>
#include <bitset>
#define chmin(a, b) ((a)=min((a), (b)))
#define chmax(a, b) ((a)=max((a), (b)))
#define fs first
#define sc second
#define eb emplace_back
using namespace std;

typedef long long ll;
typedef pair<int, double> P;
typedef tuple<int, int, int> T;

const ll MOD=1e9+7;
const ll INF=1e18;
const double pi=acos(-1);
const double eps=1e-10;

int dx[]={1, 0, -1, 0};
int dy[]={0, -1, 0, 1};

void dijkstra(int s, int g, vector<vector<P>> &G){
    vector<int> pv(110, 0);
    vector<double> dist(110, 1e9);
    pv[s] = -1;
    priority_queue<P, vector<P>, greater<P>> que;
    dist[s] = 0;
    que.push(P(0, s));

    while(!que.empty()){
        ll ccost = que.top().first;
        ll cv = que.top().second;
        que.pop();
        if(dist[cv] < ccost) continue;

        for(auto x : G[cv]){
            ll nv = x.first;
            ll ncost = x.second;
            if(dist[nv] > dist[cv] + ncost){
                dist[nv] = dist[cv] + ncost;
                pv[nv] = cv;
                que.push(P(dist[nv], nv));
            }
        }
    }

    if(dist[g] == 1e9){
        cout << "NA" << endl;
    }
    else{
        vector<int> ans;
        for(int i=g; i!=-1; i=pv[i]){
            ans.eb(i+1);
        }

        for(int i=ans.size()-1; i>=0; i--){
            cout << ans[i] << " \n"[i == 0];
        }
    }
}

int main(){
    while(1){
        int n; cin>>n;
        if(n == 0) return 0;

        vector<int> b(n), x(n), y(n);
        for(int i=0; i<n; i++){
            cin>>b[i]>>x[i]>>y[i];
            b[i]--;
        }

        vector<vector<P>> G(110);
        for(int i=0; i<n; i++){
            for(int j=i+1; j<n; j++){
                double cost = sqrt(abs(y[i] - y[j]) * abs(y[i] - y[j]) + abs(x[i] - x[j]) * abs(x[i] - x[j]));

                if(50.0 < cost) continue;

                G[b[i]].eb(P(b[j], cost));
                G[b[j]].eb(P(b[i], cost));
            }
        }

        int m; cin>>m;
        while(m--){
            int s, g; cin>>s>>g;
            s--, g--;
            dijkstra(s, g, G);
        }
    }
}

C++: #include <iostream>
#include <algorithm>
#include <cmath>
#include <vector>

struct bill{int n, x, y;};

double len[1001][1001], dist[1001];
int used[1001], prev[1001];
const double INF = 10000000;

std::vector<int> dijkstra(int s, int e){
	std::fill(dist, dist+1001, INF);
	std::fill(used, used+1001, 0);
	std::fill(prev, prev+1001, 0);

	dist[s] = 0;
	while(1){
		int v = -1;
		for(int u=1;u<1001;u++){
			if(!used[u] && (v==-1 || dist[u]<dist[v]))v=u;
		}
		if(v == -1)break;
		used[v] = 1;
		for(int u=1;u<1001;u++){
			if(dist[u] > dist[v]+len[v][u])
				dist[u] = dist[v]+len[v][u], prev[u] = v;
		}
	}
	std::vector<int> res;
	if(dist[e] == INF)res.push_back(-1);
	else{
		res.push_back(e);
		int v = e;
		while(v != s){
			v = prev[v];
			res.push_back(v);
		}
		std::reverse(res.begin(), res.end());
		return res;
	}
}


int main(){
	int n;
	while(std::cin >> n, n){
		for(int i=1;i<1001;i++)
		 	for(int j=1;j<1001;j++)
		 		len[i][j] = INF;

		std::vector<bill> bs;
		for(int i=n;i;i--){
			bill b;
			std::cin >> b.n >> b.x >> b.y;
			bs.push_back(b);
		}

		for(int i=0;i<bs.size()-1;i++){
			for(int j=i+1;j<bs.size();j++){
				double x = bs[i].x-bs[j].x, y = bs[i].y-bs[j].y, dist = sqrt(x*x+y*y);
				if(dist <= 50){
					len[bs[i].n][bs[j].n] = dist;
					len[bs[j].n][bs[i].n] = dist;
				}
			}
		}

		int m;
		std::cin >> m;
		for(;m;m--){
			int start, end;
			std::cin >> start >> end;
			std::vector<int> res = dijkstra(start, end);
			if(res[0] == -1)std::cout << "NA\n";
			else{
				for(int i=0;i<res.size();i++){
					std::cout << res[i] << (i+1-res.size()?" ":"\n");
				}
			}
		}
	}
}

C++: #include<iostream>
#include<cmath>
#include<queue>
#include<vector>
#include<cstring>
#include<functional>
using namespace std;
typedef pair<double, int> P;
priority_queue<P, vector<P>, greater<P>> Q;
#define MAX_N 1005
int x[MAX_N], y[MAX_N]; double dist[MAX_N];
vector<int>path[MAX_N]; vector<P>X[MAX_N];
void dijkstra(int a, int b) {
	memset(dist, 1e+9, sizeof(dist));
	for (int i = 0; i < MAX_N; i++) { path[i].clear(); dist[i] = 1e+9; }
	Q.push(make_pair(0.0, a)); dist[a] = 0; path[a].push_back(a);
	while (!Q.empty()) {
		pair<double, int>pa = Q.top(); Q.pop();
		double a1 = pa.first; int a2 = pa.second;
		for (int i = 0; i < X[a2].size(); i++) {
			int to = X[a2][i].second; double dis = X[a2][i].first;
			if (dist[to] > a1 + dis) {
				dist[to] = a1 + dis; path[to].clear();
				path[to] = path[a2]; path[to].push_back(to);
				Q.push(make_pair(dist[to], to));
			}
		}
	}
	if (path[b].size() == 0) { cout << "NA" << endl; }
	else {
		for (int i = 0; i < path[b].size(); i++) { if (i) { cout << ' '; } cout << path[b][i]; }
		cout << endl;
	}
}
int main() {
	int N, Q, s, g, a, b, c;
	while (true) {
		for (int i = 0; i < MAX_N; i++) { X[i].clear(); }
		cin >> N; if (N == 0) { break; }
		for (int i = 0; i < N; i++) { cin >> a >> b >> c; x[a] = b; y[a] = c; }
		for (int i = 1; i <= N; i++) {
			for (int j = 1; j <= N; j++) {
				double dist2 = sqrtl((x[i] - x[j])*(x[i] - x[j]) + (y[i] - y[j])*(y[i] - y[j]));
				if (dist2 <= 50.0) {
					X[i].push_back(make_pair(dist2, j));
				}
			}
		}
		cin >> Q;
		for (int i = 0; i < Q; i++) { 
			cin >> s >> g; dijkstra(s, g); 
		}
	}
	return 0;
}