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])
			}
		}
	}
}

Python: # AOJ 0200 Traveling Alone: One-way Ticket of Youth
# Python3 2018.6.24 bal4u
# ワーシャルフロイド法

INF = 0x7fffffff

while 1:
	n, m = map(int, input().split())
	if n == 0: break
	tim = [[INF for j in range(m)] for i in range(m)]
	fee = [[INF for j in range(m)] for i in range(m)]
	for i in range(m): tim[i][i] = fee[i][i] = 0;
	for i in range(n):
		a, b, c, t = map(int, input().split())
		a -= 1
		b -= 1
		if fee[a][b] > c: fee[a][b] = fee[b][a] = c
		if tim[a][b] > t: tim[a][b] = tim[b][a] = t
	for k in range(m):
		for i in range(m):
			for j in range(m):
				if fee[i][k]+fee[k][j] < fee[i][j]: fee[i][j] = fee[i][k]+fee[k][j]
				if tim[i][k]+tim[k][j] < tim[i][j]: tim[i][j] = tim[i][k]+tim[k][j]
	k = int(input())
	for i in range(k):
		p, q, r = map(int, input().split())
		if (r): print(tim[p-1][q-1])
		else:   print(fee[p-1][q-1])

Python: # -*- coding: utf-8 -*-
"""
http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=0200

"""
import sys
from sys import stdin
input = stdin.readline


def warshallFloyd(V, dp):
    for k in range(1, V):
        for i in range(1, V):
            for j in range(1, V):
                if dp[i][k][0] + dp[k][j][0] < dp[i][j][0]:
                    dp[i][j][0] = dp[i][k][0] + dp[k][j][0]
                if dp[i][k][1] + dp[k][j][1] < dp[i][j][1]:
                    dp[i][j][1] = dp[i][k][1] + dp[k][j][1]


def main(args):
    while True:
        n, m = map(int, input().split())
        if n == 0 and m == 0:
            break
        dp = [[[float('inf'), float('inf')]] * (m+1) for _ in range(m+1)]
        for i in range(m+1):
            dp[i][i] = [0, 0]
        for _ in range(n):
            a, b, cost, time = map(int, input().split())
            dp[a][b] = [time, cost]
            dp[b][a] = [time, cost]

        warshallFloyd(m+1, dp)

        k = int(input())
        for _ in range(k):
            p, q, r = map(int, input().split())
            if r == 0:          #  cost
                print(dp[p][q][1])
            else:               #  time
                print(dp[p][q][0])



if __name__ == '__main__':
    main(sys.argv[1:])

Python: from heapq import heappop, heappush


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 Dijkstra:
    """Single root shortest path by Dijkstra."""

    def __init__(self, graph, s):
        self.dist_to = [float('inf') for _ in range(graph.num_nodes() + 1)]
        self.dist_to[s] = 0
        pq = []
        heappush(pq, (0, s))
        while pq:
            w, a = heappop(pq)
            if self.dist_to[a] < w:
                continue
            for edge in graph.adj(a):
                if self.dist_to[edge.b] > self.dist_to[edge.a] + edge.weight:
                    self.dist_to[edge.b] = self.dist_to[edge.a] + edge.weight
                    heappush(pq, (self.dist_to[edge.b], edge.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)

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