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
			c_matrix[b-1][a-1] = c
			t_matrix[a-1][b-1] = t
			t_matrix[b-1][a-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])
			}
		}
	}
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef pair<int,int > P;
const int INF = 1 << 30;
int Dijkstra(int s,int g,int r);

int m,n;

int min_cost[2][111];

typedef struct{
  vector<int>edge_to;
  vector<int>edge_cost[2];
}Node_data;

Node_data Graph[111];

priority_queue<P ,vector< P >, greater< P > >que;

int main(){
  int a,b,c,d,k;
  int s,g,r;
  while(1){
    cin >> m >> n;
    if(m == 0 && n == 0)break;
    for(int i = 0;i < m;i++){
      scanf("%d %d %d %d",&a,&b,&c,&d);
      Graph[a - 1].edge_to.push_back(b - 1);
      Graph[a - 1].edge_cost[0].push_back(c);
      Graph[a - 1].edge_cost[1].push_back(d);
      Graph[b - 1].edge_to.push_back(a - 1);
      Graph[b - 1].edge_cost[0].push_back(c);
      Graph[b - 1].edge_cost[1].push_back(d);
    }
    cin >> k;
    for(int i = 0;i < k;i++){

      cin >> s >> g >> r;

      for(int j = 0;j < n;j++){
	min_cost[r][j] = INF;
      }
      cout << Dijkstra(s - 1,g - 1,r) << endl;
    }
  }
  return(0);
}

int Dijkstra(int s,int g,int r){
  int node,cost;
  int newnode,newcost;
  min_cost[r][s] = 0;
  P a;
  a.first = 0;
  a.second = s;
  que.push(a);
  while(!que.empty()){
    node = que.top().second;
    cost = que.top().first;
    que.pop();
    if(node == g)return cost;
    if(cost > min_cost[r][node])continue;
    for(int i = 0;i < Graph[node].edge_to.size();i++){
      newnode = Graph[node].edge_to[i];
      newcost = cost + Graph[node].edge_cost[r][i];
      if(min_cost[r][newnode] > newcost){
	min_cost[r][newnode] = newcost;
	a.first = newcost;
	a.second = newnode;
	que.push(a);
      }
    }
  }
  return -1;
}

C++: #include<iostream>
#include<algorithm>
#define MAX 1000000
using namespace std;
int main(){
	int n, m, a, b, cost, time, k, p, q, r, point = 0;
	int cost_[101][101], time_[101][101], k_[101];
	for (int i = 0; i < 101; i++){
		for (int l = 0; l < 101; l++){
			cost_[i][l] = MAX;
			time_[i][l] = MAX;
		}
	}
	cin >> n >> m;
	while (n != 0 && m != 0){
		for (int i = 0; i < n; i++){
			cin >> a >> b >> cost >> time;
			cost_[a][b] = cost;
			time_[a][b] = time;
		}
		cin >> k;
		for (int i = 0; i < k; i++){
			cin >> p >> q >> r;
			k_[point] = p;
			k_[point + 1] = q;
			k_[point + 2] = r;
			point += 3;
		}point = 0;
		for (int i = 1; i <= m; i++){
			for (int j = 1; j <= m; j++){
				for (int o = 1; o <= m; o++){
					if (cost_[j][i] != MAX && cost_[i][o] != MAX &&
						time_[j][i] != MAX && time_[i][o] != MAX){
						cost_[j][o] = min(cost_[j][o], cost_[j][i] + cost_[i][o]);
						time_[j][o] = min(time_[j][o], time_[j][i] + time_[i][o]);
					}
				}
			}
		}
		for (int i = 0; i < k; i++){
			if (k_[point + 2] == 0){
				cout << cost_[k_[point]][k_[point + 1]] << endl;
			}
			else cout << time_[k_[point]][k_[point + 1]] << endl;
			point += 3;
		}
		cin >> n >> m;
	}
	return 0;
}

C++: #include <bits/stdc++.h>
#define rep(i, n) for(int i = 0; i < (int)(n); i++)
#define pb push_back
#define mp make_pair

using namespace std;

typedef long long ll;
typedef pair<int, int> P;

const int MOD = 1000000007;
//const int INF = 2000000000;
const int INF = (1 << 21);

int c[1000][1000];
int t[1000][1000];

int main() {
    while(true) {
        int n, m;
        cin >> n >> m;
        if(n == 0 && m == 0) break;

        rep(i, m) {
            rep(j, m) {
                c[i][j] = INF;
                t[i][j] = INF;
            }
            c[i][i] = 0;
            t[i][i] = 0;
        }
        rep(i, n) {
            int a, b, cost, time;
            cin >> a >> b >> cost >> time;
            c[a - 1][b - 1] = cost;
            c[b - 1][a - 1] = cost;
            t[a - 1][b - 1] = time;
            t[b - 1][a - 1] = time;
        }

        rep(k, m) {
            rep(i, m) {
                rep(j, m) {
                    /*if(c[i][k] != INF && c[k][j] != INF)*/ c[i][j] = min(c[i][j], c[i][k] + c[k][j]);
                    /*if(t[i][k] != INF && t[k][j] != INF)*/ t[i][j] = min(t[i][j], t[i][k] + t[k][j]);
                }
            }
        }

        int k;
        cin >> k;
        rep(i, k) {
            int p, q, r;
            cin >> p >> q >> r;
            if(r == 0) cout << c[p - 1][q - 1] << endl;
            else cout << t[p - 1][q - 1] << endl;
        }
    }

    return 0;
}