Go: // Warshall–Floyd Algorithm

package main

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

var scanner = bufio.NewScanner(os.Stdin)

const INF = 0x7FFFFFFF

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
				} else {
					c_dist[i][j] = c_matrix[i][j]
				}
				if c_matrix[i][j] == 0{
					c_prev[i][j] = -1
				} else {
					c_prev[i][j] = i
				}
				if t_matrix[i][j] == 0{
					t_dist[i][j] = INF
				} else {
					t_dist[i][j] = t_matrix[i][j]
				}
				if t_matrix[i][j] == 0{
					t_prev[i][j] = -1
				} else {
					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]
					t_newlen := t_dist[i][k] + t_dist[k][j]
					if c_newlen < c_dist[i][j] {
						c_dist[i][j] = c_newlen
						c_prev[i][j] = c_prev[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])
			}
		}
	}
}

Python: import math


class WeightedEdge:
    """Weighted edge."""

    def __init__(self, a, b, weight):
        self.a = a
        self.b = b
        self.weight = weight

    def __repr__(self):
        return "(%d - %d: %d)" % (self.a, self.b, self.weight)

    def __lt__(self, other):
        return self.a < other.b


class EdgeWeightedGraph:
    """Undirected Edge-weighted graph (1-n indexed)."""

    def __init__(self, V):
        self.__adj = [[] for _ in range(V + 1)]

    def add_edge(self, a, b, weight):
        self.__adj[a].append(WeightedEdge(a, b, weight))
        self.__adj[b].append(WeightedEdge(b, a, weight))

    def adj(self, a):
        return self.__adj[a]

    def num_nodes(self):
        return len(self.__adj) - 1


class FloydWarshall:
    """u a.k.a. WarshallFloyd.

    Find shortest paths between each combination of vertices in a graph.
    ???3????????????a, b, c???????????§???a???b???c??¨????????????a???c??¨??????????????????????????°a???c????????¢?????´??°?????????
    ????????????for???????????±?????????????????????????????¨.
    O(V^3)
    """

    # graph has nodes [1, n]
    def __init__(self, graph):
        n = graph.num_nodes()
        nodes = range(1, n + 1)
        self.__mat = [[math.inf for _ in range(n + 1)] for _ in range(n + 1)]
        self.__init_mat(graph, nodes)
        self.__compute(nodes)

    def __init_mat(self, graph, nodes):
        for i in nodes:
            self.__mat[i][i] = 0

        for i in nodes:
            for edge in graph.adj(i):
                self.__mat[edge.a][edge.b] = edge.weight

    def __compute(self, nodes):
        for i in nodes:  # via
            for j in nodes:  # from
                for k in nodes:  # to
                    val = self.__mat[j][i] + self.__mat[i][k]
                    if self.__mat[j][k] > val:
                        self.__mat[j][k] = val

    def distance(self, a, b):
        return self.__mat[a][b]


if __name__ == '__main__':
    while True:
        n, m = map(int, input().split())
        if n == 0 and m == 0:
            break

        g_cost = EdgeWeightedGraph(m)
        g_time = EdgeWeightedGraph(m)
        for _ in range(n):
            a, b, cost, time = map(int, input().split())
            g_cost.add_edge(a, b, cost)
            g_time.add_edge(a, b, time)

        fw_cost = FloydWarshall(g_cost)
        fw_time = FloydWarshall(g_time)
        k = int(input())
        for _ in range(k):
            p, q, r = map(int, input().split())
            if r == 0:
                ans = fw_cost.distance(p, q)
            else:
                ans = fw_time.distance(p, q)
            print(ans)

Python: import sys

inf = sys.maxsize

# 入力:graphと始点s
# 出力:始点sから各頂点tへの距離dist
def shortestPath(graph, s):
    n = len(graph)

    dist    = [inf for _ in range(n)]
    visited = [False for _ in range(n)]
    dist[s] = 0

    while True:
        idx, u  = -1, inf
        for i in range(n):
            if not visited[i] and dist[i] < u:
                idx = i
                u = dist[i]
        
        if u == inf: break
        
        visited[idx] = True

        for (next, w) in graph[idx]:
            newdist = w + dist[idx]
            if newdist < dist[next]:
                dist[next] = newdist
    return dist

def main():
    while True:
        n, m = map(int, input().split())
        if n == 0 and m == 0: return

        # 隣接リスト
        c_graph = [[] for _ in range(m)]
        t_graph = [[] for _ in range(m)]
    
        for i in range(n):
            a, b, cost, time = map(int, input().split())
            a -= 1
            b -= 1
            c_graph[a].append((b, cost))
            c_graph[b].append((a, cost))
            t_graph[a].append((b, time))
            t_graph[b].append((a, time))
            
        c_dist = [shortestPath(c_graph, s) for s in range(m)]
        t_dist = [shortestPath(t_graph, s) for s in range(m)]
            
        k = int(input())
        for i in range(k):
            p, q, r = map(int, input().split())
            p -= 1
            q -= 1
            if r == 0:
                print(c_dist[p][q])
            else:
                print(t_dist[p][q])

main()