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<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(); }
	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 = 0; i < N; i++) {
			for (int j = 0; j < N; j++) {
				double dist2 = (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;
}

C++: #include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <vector>
#include <cmath>
using namespace std;

#define MAX 1100
#define INF (1<<29)
#define EPS 1e-9

struct Point{
  int x, y, id;
};

vector<Point> bill;
double dist[MAX][MAX];

int V;

void init(){
  bill.clear();
  for(int i = 0 ; i < MAX ; i++){
    for(int j = 0 ; j < MAX ; j++){
      dist[i][j] = INF;
      if(i == j) dist[i][j] = 0;
    }
  }
}

int prev[MAX];
void dijkstra(int s){
  int d[MAX];
  bool used[MAX];
  for(int i = 0 ; i < MAX ; i++){
    d[i] = INF;
    used[i] = false;
    prev[i] = -1;
  }
  //fill(d, d+MAX, INF);
  //fill(used, used+MAX, false);
  //fill(prev, prev+MAX, -1);
  d[s] = 0;
  
  while(true){
    int v = -1;
    for(int u = 0 ; u < V ; u++){
      if(!used[u] && (v == -1 || d[u] < d[v])) v = u;
    }
    if(v == -1) break;
    used[v] = true;
    
    for(int u = 0 ; u < V ; u++){
      if(d[u] > d[v] + dist[v][u]){
	d[u] = d[v] + dist[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;
}

double getDist(int from, int to){
  double ret = sqrt(( ((bill[from].x - bill[to].x)*(bill[from].x - bill[to].x)) +
			     ((bill[from].y - bill[to].y)*(bill[from].y - bill[to].y)) ) );
  return ret;
}
  
int main(){
  while(cin >> V, V){
    bill.clear();
    init();
    Point p;
    for(int i = 0 ; i < V ; i++){
      cin >> p.id >> p.x >> p.y;
      p.id--;
      bill.push_back(p);
    }
    
    for(int i = 0 ; i < V ; i++){
      for(int j = i ; j < V ; j++){
	if(i == j) continue;
	double distance = getDist(bill[i].id, bill[j].id);
	//if(dis >= 50 + EPS) continue;
	if(distance <= 50.0 + EPS){
	dist[bill[i].id][bill[j].id] = dist[bill[j].id][bill[i].id] = distance;
	}
      }
    }
    int m;    
    cin >> m;
    int s, g;
    for(int cs = 0 ; cs < m ; cs++){
      cin >> s >> g;
      s--, g--;
      dijkstra(s);
      vector<int> ans_path;
      ans_path = get_path(g);
      if(ans_path.size() <= 1) cout << "NA" << endl;
      else{
	for(int i = 0 ; i < (int)ans_path.size() ; i++){
	  if(i == (int)ans_path.size()-1) cout << ans_path[i]+1 << endl;
	  else cout << ans_path[i]+1 << ' ';
	}
      }
      ans_path.clear();
    } 
  }
  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

typedef pair<double, int> P;

int n;

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

    vector<int> prev(n, -1);

    while(que.size()){
        double ccost;
        int cv;
        tie(ccost, cv) = que.top();
        que.pop();

        if(dist[cv] < ccost) continue;

        for(auto x : G[cv]){
            int nv;
            double ncost;
            tie(nv, ncost) = x;

            if(dist[cv] + ncost < dist[nv]){
                dist[nv] = dist[cv] + ncost;
                prev[nv] = cv;
                que.emplace(dist[nv], nv);
            }
        }
    }

    if(dist[g] == 1e9){
        cout << "NA" << endl;
    }
    else{
        vector<int> ans;
        for(int i=g; i!=-1; i=prev[i]){
            ans.emplace_back(i);
        }
        reverse(ans.begin(), ans.end());

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

int main(){
    while(1){
        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<pair<int, double>>> G(n);
        for(int i=0; i<n; i++){
            for(int j=i+1; j<n; j++){
                double cdist = sqrt(abs(x[i] - x[j]) * abs(x[i] - x[j]) + abs(y[i] - y[j]) * abs(y[i] - y[j]));
                if(50 < cdist) continue;
                G[b[i]].emplace_back(b[j], cdist);
                G[b[j]].emplace_back(b[i], cdist);
            }
        }

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