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<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 < 1000; i++){
			for(int j = i+1; j < 1000; 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"); break;
			}

			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;
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <set>
#include <map>
#include <list>
#include <queue>
#include <algorithm>
#include <sstream>
#include <cmath>
#include <cassert>

using namespace std;

const int MAX_V = 1001;
const int INF   = INT_MAX;

struct Edge {
  int to;
  int cost;
};

int          V;
vector<Edge> G[MAX_V];
int          d[MAX_V];
int          prev[MAX_V];

void dijkstra(int s) {
  typedef pair<int, int> P;
  priority_queue<P, vector<P>, greater<P> > que;
  fill(d, d + V, INF);
  fill(prev, prev + V, -1);
  d[s] = 0;
  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 < (int)G[v].size(); i++) {
      Edge e = G[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));
      }
    }
  }
}

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;
}


struct Building {
  int x;
  int y;
};

int distance2(Building *b1, Building *b2) {
  int dx = b1->x - b2->x;
  int dy = b1->y - b2->y;
  return dx * dx + dy * dy;
}

int name[MAX_V];
int rname[MAX_V];
Building building[MAX_V];

int main() {
  while (true) {
    int n;
    cin >> n;
    if (n == 0)
      break;
    V = n;

    for (int i = 0; i < n; i++) {
      G[i].clear();
    }
    for (int i = 0; i < n; i++) {
      int b;
      cin >> b;
      name[i] = b;
      rname[b] = i;
      cin >> building[i].x >> building[i].y;
    }
    for (int i = 0; i < n; i++) {
      for (int j = i + 1; j < n; j++) {
        Building *b1 = building + i;
        Building *b2 = building + j;
        int       d2 = distance2(b1, b2);

        if (d2 <= 50 * 50) {
          int d1 = sqrt(d2);
          Edge e1 = {j, d1};
          G[i].push_back(e1);
          Edge e2 = {i, d1};
          G[j].push_back(e2);
        }
      }
    }
    int m;
    cin >> m;
    for (int i = 0; i < m; i++) {
      int s;
      int g;
      cin >> s >> g;
      dijkstra(rname[s]);
      if (d[rname[g]] == INF) {
        cout << "NA" << endl;
      } else {
        vector<int> path = get_path(rname[g]);
        for (int j = 0; j < (int)path.size(); j++) {
          cout << name[path[j]];
          if (j < (int)path.size() - 1)
            cout << " ";
        }
        cout << endl;
      }
    }
  }
  return 0;
}