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: max_ = 1001
def solv(p,q):
    global costs
    global times
    global stack
    if times[p][q] < max_:
        #最短経路算出済み
        return costs[p][q],times[p][q]

    if p == q:
        return 0,0

    min_cost = max_
    min_time = max_
    stack.append(p)

    for s in senro :
        if (s[0] == p or s[1] == p) :
            next_ = s[1] if s[0]==p else s[0]
            if next_ in stack: #経過済みは無視
                continue

            c,t = solv(next_,q)
            min_cost = min(c + s[2],min_cost)
            min_time = min(t + s[3],min_time)
    
    costs[p][q] = min_cost
    times[p][q] = min_time

    stack.pop()

    return min_cost,min_time

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

    costs = [[max_ for i in range(m+1)] for j in range(m+1)]
    times = [[max_ for i in range(m+1)] for j in range(m+1)]

    senro = [list(map(int,input().split())) for i in range(n)]
    stack=[]

    k = int(input())
    for i in range(k):
        p,q,r = list(map(int,input().split()))
        solv(p,q)
        print(times[p][q] if r==1 else costs[p][q])

Python: from heapq import heappop as hpop
from heapq import heappush as hpush

while True:
  n, m = map(int, input().split())
  
  if not n:
    break
  
  cost_edges = [[] for _ in range(m)]
  time_edges = [[] for _ in range(m)]

  for _ in range(n):
    a, b, c, t = map(int, input().split())
    cost_edges[a - 1].append((c, b - 1))
    cost_edges[b - 1].append((c, a - 1))
    time_edges[a - 1].append((t, b - 1))
    time_edges[b - 1].append((t, a - 1))
  
  k = int(input())

  for _ in range(k):
    start, goal, r = map(int ,input().split())
    start -= 1
    goal -= 1
    
    if r:
      edges = time_edges
    else:
      edges = cost_edges

    que = [(0, start)]
    visited = [False for _ in range(m)]
    
    while que:
      score, station = hpop(que)
      visited[station] = True
      
      if station == goal:
        print(score)
        break

      for c, to_station in edges[station]:
        if not visited[to_station]:
          hpush(que, (score + c, to_station))

Python: cost_ans = []
time_ans = []

def set_ans(cost , time):
    cost_ans.append(cost)
    time_ans.append(time)

class Sta(object):
    """station"""
    def __init__(self, station_name):
        super(Sta, self).__init__()
        self.station_name = station_name
        self.route = []

    def add_route(self, route):
        self.route.append(route)



class Route(object):
    """route"""
    def __init__(self, cost, time, next_station):
        super(Route, self).__init__()
        self.time = time
        self.cost = cost
        self.next_station = next_station

def search_route(now_station, gool_station, cost, time):
    """search route"""

    if now_station.station_name == gool_station.station_name:
        set_ans(cost, time)
        return

    elif len(now_station.route) == 0:
        return

    for r in now_station.route:
        search_route(
                r.next_station,
                gool_station,
                cost + r.cost,
                time + r.time)
def main():

    while True:
        cost_ans = []
        time_ans = []

        n,m = map(int, raw_input().split())
        if n == 0 and m == 0:
            return

        stations = [Sta(x) for x in xrange(1,m+1) ]

        for i in xrange(n):
            a, b, cost, time = map(int, raw_input().split())
            tmp = Route(cost, time, stations[b-1])
            stations[a-1].add_route(tmp)

        k = input()
        for i in xrange(k):
            p, q, r = map(int, raw_input().split())
            search_route(stations[p-1], stations[q-1], 0, 0)
            if r == 0:
                print(min(cost_ans))
            else:
                print(min(time_ans))



if __name__ == '__main__':
    main()