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 copy as c
CEIL = 2000000000

def exploreMin(now, goal, mode, history, ans, lines):
    #mode=0: MinCost;mode=1: MinTime
    #print(lines)
    if now == goal:
        #print('??\????????±??????')
        return ans
    if now in history: return CEIL
    minCostOrTime = CEIL
    for destination in lines[now]:
        if minCostOrTime < destination[mode+1]: continue
        exploreAns = exploreMin(destination[0], goal, mode, c.deepcopy(history)+[now],
                                ans+destination[mode+1], lines)
        #print(exploreAns)
        if minCostOrTime > exploreAns: minCostOrTime = exploreAns
    return minCostOrTime
'''
def findMin(start, goal, mode):
    minAnswer=100000
    if minAnswer > xplore(start, goal, mode, []):

    return minAnswer
'''
def dprint(a):
    print('debug:', end='')
    print(a)

def main():
    input1 = input().split(' ')
    #dprint(input1)
    if input1[0] == '0': return True
    lines=[[] for i in range(int(input1[1]))]
    for lineIndex in range(int(input1[0])):
        input2 = input().split(' ')
        #print('debug:', end='')
        #print(input2)
        lines[int(input2[0])-1].append([int(input2[1])-1, int(input2[2]), int(input2[3])])
        lines[int(input2[1])-1].append([int(input2[0])-1, int(input2[2]), int(input2[3])])
    #print(lines[0][0][1])
    setnum = int(input())
    #a = '\n'
    for out in range(setnum):
        #if out==setnum-1: a=''
        input3 = input().split(' ')
        #print([].append(1))
        print(exploreMin(int(input3[0])-1, int(input3[1])-1, int(input3[2]), [], 0, lines))

if __name__ == '__main__':
    while True:
        if main(): break

Python: import sys
import heapq as h

inf = sys.maxsize

# おまじない
class heapq:
    def __init__(self):
        self.q = []

    def push(self,v):
        h.heappush(self.q, v)
    
    def pop(self):
        return h.heappop(self.q)

    def is_empty(self):
        return len(self.q) == 0

# 入力:graphと始点s
# 出力:始点sから各頂点tへの距離dist
def shortestPath0(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 shortestPath1(graph, s):
    n = len(graph)

    dist    = [inf for _ in range(n)]
    visited = [False for _ in range(n)]
    
    q = heapq()
    q.push((0, s))

    while not q.is_empty():
        (cur_dist, v) = q.pop()

        if visited[v] or dist[v] <= cur_dist:
            continue

        dist[v] = cur_dist
        visited[v] = True

        for next, w in graph[v]:
            if not visited[next] and dist[v] + w < dist[next]:
                q.push((dist[v] + w, next))

    return dist

def main():
    while True:
        n, m = map(int, input().split())
        if n == 0 and m == 0:
            break
        # 隣接リスト
        tgraph = [[] for _ in range(m)]
        cgraph = [[] for _ in range(m)]
        
        for i in range(n):
            a, b, cost, time = map(int, input().split())
            a -= 1
            b -= 1
            cgraph[a].append((b, cost))
            cgraph[b].append((b, cost))
            tgraph[a].append((b, time))
            tgraph[b].append((b, time))
            
        c_dist = [shortestPath0(cgraph, s) for s in range(m)]
        t_dist = [shortestPath0(tgraph, 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()