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]
					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++: #include <iostream>
#include <string>
#include <algorithm>
#include <functional>
#include <vector>
#include <utility>
#include <cstring>
#include <iomanip>
#include <numeric>
#include <cmath>
#include <queue>
#include <map>
using namespace std;
typedef long long ll;
typedef pair<int, int> P;
const int INF = 1<<30; 
const int MOD = 1e9 + 7;
const int dy[] = {1, 0, -1, 0};
const int dx[] = {0, 1, 0, -1};
const int MAX_N = 3010;
int n, m;
struct edge { int to, cost, time; };
vector<edge> G[MAX_N];
int solve(int start, int goal, int flag)
{
    vector<int> res(MAX_N, INF);
    priority_queue<P, vector<P>, greater<P>> que;
    que.push(P(0, start));
    res[start] = 0;
    while(not que.empty())
    {
        int w = que.top().first, v = que.top().second;
        que.pop();
        if(res[v] < w) continue;
        for(int u = 0; u < G[v].size(); u++)
        {
            edge e = G[v][u];
            int num = (flag ? e.time : e.cost);
            if(w + num < res[e.to])
            {
                res[e.to] = w + num;
                que.push(P(res[e.to], e.to));
            }
        }
    }
    return res[goal];
}
int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    while(cin >> n >> m, n | m)
    {
        for(int i = 0; i < MAX_N; i++) G[i].clear();
        for(int i = 0; i < n; i++)
        {
            int a, b, c, t; cin >> a >> b >> c >> t;
            a--, b--;
            G[a].push_back({b, c, t});
            G[b].push_back({a, c, t});
        }
        int k; cin >> k;
        for(int i = 0; i < k; i++)
        {
            int p, q, f; cin >> p >> q >> f;
            p--, q--;
            cout << solve(p, q, f) << endl;
        }
    }
    return 0;
}

C++: #include<cstdio>
#include<algorithm>
#include<iostream>
#include<vector>
#include<set>

using namespace std;

#define rep(i,n) for(int i=0;i<int(n);i++)
#define reps(i,n) for(int i=1;i<=int(n);i++)

int main(){
	while(1){
		int n,m;
		vector<pair<int,int> > a[111][2];
		
		cin>>n>>m;
		if(n==0)break;
		
		
		int froid[111][111][2];
		rep(i,111)rep(j,111)rep(k,2)froid[i][j][k]=1010000000;
		
		
		rep(i,n){
			int a,b,c,d;
			cin>>a>>b>>c>>d;
			
			froid[a][b][0]=c;
			froid[b][a][0]=c;
			froid[a][b][1]=d;
			froid[b][a][1]=d;
			
		}
		
		rep(p,2){
			reps(k,n){
				reps(i,n){
					reps(j,n){
						froid[i][j][p] = min(froid[i][j][p],froid[i][k][p]+froid[k][j][p]);
					}
				}
			}
		}
		
		int k;
		cin>>k;
		
		rep(i,k){
			int a,b,c;
			cin>>a>>b>>c;
			
			printf("%d\n",froid[a][b][c]);
		}
	}
}