Go: // Warshall–Floyd Algorithm

package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
	"strings"
)

var scanner = bufio.NewScanner(os.Stdin)

const INF = 2000000000

func main() {
	for scanner.Scan() {
		buf := strings.Split(scanner.Text(), " ")
		n, _ := strconv.Atoi(buf[0])
		m, _ := strconv.Atoi(buf[1])
		if n == 0 && m == 0 {
			break
		}
		c_matrix := make([][]int, m)
		for i := range c_matrix {
			c_matrix[i] = make([]int, m)
		}
		t_matrix := make([][]int, m)
		for i := range t_matrix {
			t_matrix[i] = make([]int, m)
		}
		for i := 0; i < n; i++ {
			scanner.Scan()
			buf_ := strings.Split(scanner.Text(), " ")
			a, _ := strconv.Atoi(buf_[0])
			b, _ := strconv.Atoi(buf_[1])
			c, _ := strconv.Atoi(buf_[2])
			t, _ := strconv.Atoi(buf_[3])
			c_matrix[a-1][b-1] = c
			t_matrix[a-1][b-1] = t
		}
		c_dist := make([][]int, m)
		c_prev := make([][]int, m)
		t_dist := make([][]int, m)
		t_prev := make([][]int, m)
		for i := 0; i < m; i++ {
			c_dist[i] = make([]int, m)
			c_prev[i] = make([]int, m)
			t_dist[i] = make([]int, m)
			t_prev[i] = make([]int, m)
		}
		for i := 0; i < m; i++ {
			for j := 0; j < m; j++ {
				if c_matrix[i][j] == 0 {
					c_dist[i][j] = INF
					c_prev[i][j] = -1
				} else {
					c_dist[i][j] = c_matrix[i][j]
					c_prev[i][j] = i
				}
				if t_matrix[i][j] == 0 {
					t_dist[i][j] = INF
					t_prev[i][j] = -1
				} else {
					t_dist[i][j] = t_matrix[i][j]
					t_prev[i][j] = i
				}
			}
			c_dist[i][i] = 0
			t_dist[i][i] = 0
		}
		for k := 0; k < m; k++ {
			for i := 0; i < m; i++ {
				for j := 0; j < m; j++ {
					c_newlen := c_dist[i][k] + c_dist[k][j]
					if c_newlen < c_dist[i][j] {
						c_dist[i][j] = c_newlen
						c_prev[i][j] = c_prev[k][j]
					}
				}
			}
		}
		for k := 0; k < m; k++ {
			for i := 0; i < m; i++ {
				for j := 0; j < m; j++ {
					t_newlen := t_dist[i][k] + t_dist[k][j]
					if t_newlen < t_dist[i][j] {
						t_dist[i][j] = t_newlen
						t_prev[i][j] = t_prev[k][j]
					}

				}
			}
		}
		scanner.Scan()
		k, _ := strconv.Atoi(scanner.Text())
		for i := 0; i < k; i++ {
			scanner.Scan()
			buf_ := strings.Split(scanner.Text(), " ")
			p, _ := strconv.Atoi(buf_[0])
			q, _ := strconv.Atoi(buf_[1])
			r, _ := strconv.Atoi(buf_[2])
			switch r {
			case 0:
				fmt.Println(c_dist[p-1][q-1])
			case 1:
				fmt.Println(t_dist[p-1][q-1])
			}
		}
	}
}

C++: #define NODE 0
#define WEIGHT 1
#define COST_IDX 0
#define TIME_IDX 1
#define P_IDX 0
#define Q_IDX 1
#define R_IDX 2
#include <iostream>
#include <cstring>
using namespace std;

int n, m, k;
int weights[101][101][2];
int min_w[101][101][2];
int requests[200][3];

struct heap_queue {
  int arr[101];
  int *cmp_val;
  int lookup[101];
  int size=0;
};

bool read_input() {
  cin >> n >> m;
  if (n*m == 0) 
    return false;
  memset(weights, 0, sizeof(int)*101*101*2);
  memset(min_w, 0, sizeof(int)*101*101*2);
  for (int i = 0; i < n; i++) {
    int a, b, c, t;
    cin >> a >> b >> c >> t;
    weights[a][b][COST_IDX] = weights[b][a][COST_IDX] = c;
    weights[a][b][TIME_IDX] = weights[b][a][TIME_IDX] = t;
  }
  cin >> k;
  for (int i = 0; i < k; i++) {
    cin >> requests[i][P_IDX] >> requests[i][Q_IDX] >> requests[i][R_IDX];
  }
  return true;
}

void heap_push(int elm, heap_queue &q) {
  q.arr[q.size++] = elm;
  int above, i = q.size-1;
  while (i && q.cmp_val[q.arr[(above=(i-1)>>1)]] > q.cmp_val[q.arr[i]]) {
    int tmp = q.arr[above];
    q.arr[above] = q.arr[i];
    q.arr[i] = tmp;
    q.lookup[q.arr[i]] = i;
    i = above;
  }
  q.lookup[elm] = i;
}

int heap_pop(heap_queue &q) {
  int ret = q.arr[0];
  q.arr[0] = q.arr[--q.size];
  int below, i = 0;
  if (q.size == 1 || q.size == 0)
    return ret;
  if (q.size == 2)
    below = 1;
  else
    below = q.cmp_val[q.arr[1]] <= q.cmp_val[q.arr[2]] ? 1:2;
  while (q.cmp_val[q.arr[below]] < q.cmp_val[q.arr[i]]) {
    int tmp = q.arr[below];
    q.arr[below] = q.arr[i];
    q.arr[i] = tmp;
    q.lookup[q.arr[i]] = i;
    i = below;
    int l = (i<<1)+1, r = (i<<1)+2;
    if (l >= q.size)
      break;
    if (r >= q.size)
      below = l;
    else
      below = q.cmp_val[q.arr[l]] <= q.cmp_val[q.arr[r]] ? l:r;
  }
  return ret;
}

void change_val(int elm, heap_queue &q) {
  int i = q.lookup[elm];
  int above;
  while (i != 0 && q.cmp_val[q.arr[(above=(i-1)>>1)]] > q.cmp_val[q.arr[i]]) {
    int tmp = q.arr[above];
    q.arr[above] = q.arr[i];
    q.arr[i] = tmp;
    q.lookup[q.arr[i]] = i;
    i = above;
  }
  q.lookup[elm] = i;
}

int resolve_request(int i_th) {
  int p, q, r;
  p = requests[i_th][P_IDX];
  q = requests[i_th][Q_IDX];
  r = requests[i_th][R_IDX];

  if (min_w[p][q][r])
    return min_w[p][q][r];

  int weight_sum_map[101];
  memset(weight_sum_map, -1, sizeof(int)*101);
  
  /* starting node has weight_sum of 0 */
  weight_sum_map[p] = 0;

  int in_queue[101] = {};
  heap_queue heap_q;
  heap_q.cmp_val = weight_sum_map;
  heap_push(p, heap_q);
  in_queue[p] = 1;

  while (heap_q.size) {
    int current_node = heap_pop(heap_q);
    in_queue[current_node] = 0;
    int weight_sum = weight_sum_map[current_node];
    min_w[p][current_node][r] = weight_sum;

    if (current_node == q)
      break;
    for (int i = 1; i < 101; i++) {
      if (!weights[current_node][i][r]) 
	continue;
      int adj_node = i;
      int w = weights[current_node][adj_node][r];
      int new_weight_sum =  weight_sum + w;
      if (weight_sum_map[adj_node] == -1 || new_weight_sum < weight_sum_map[adj_node]) {
	weight_sum_map[adj_node] = new_weight_sum;
	if (!in_queue[adj_node]) {
	  heap_push(adj_node, heap_q);
	  in_queue[adj_node] = 1;
	} else {
	  change_val(adj_node, heap_q);
	}
      }
    }
  }
  return weight_sum_map[q];
}

void solve() {
  for (int i = 0; i < k; i++)
    cout << resolve_request(i) << endl;
}

int main() {
  cin.tie(0); ios::sync_with_stdio(false);
  while(read_input()) {
    solve();
  }
  return 0;
}

C++: #include<stdio.h>
#include<stdlib.h>
#include<math.h>
#include<iostream>
#include<string>
#include<algorithm>
#include<queue>
#include<utility>

using namespace std;

int n,m;

long long gc[110][110];
long long gt[110][110];

void warshallfloyd()
{
	for (int k = 0; k < m; k++)
	{
		for (int i = 0; i < m; i++)
		{
			for (int j = 0; j < m; j++)
			{
				gc[i][j] = min(gc[i][j], gc[i][k] + gc[k][j]);
				gt[i][j] = min(gt[i][j], gt[i][k] + gt[k][j]);
			}
		}
	}
}

int main(void)
{
	while (cin >> n >> m, n || m)
	{

		for (int i = 0; i < n; i++)
		{
			for (int j = 0; j < n; j++)
			{
				gc[i][j] = 9999999;
				gt[i][j] = 9999999;
			}
		}

		for (int i = 0; i < n; i++)
		{
			int a, b, c, t;

			cin >> a >> b >> c >> t;

			a--; b--;

			gc[a][b] = gc[b][a] = c;
			gt[a][b] = gt[b][a] = t;
		}

		warshallfloyd();

		int k;

		cin >> k;

		for (int i = 0; i < k;i++)
		{
			int p, q, r;

			cin >> p >> q >> r;

			p--; q--;

			if (r == 0)
			{
				cout << gc[p][q] << endl;
			}
			else
			{
				cout << gt[p][q] << endl;
			}
		}
	}

	

	return 0;
}