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])
			}
		}
	}
}

C++: #include <iostream>
#include <algorithm>
#include <cstring>
using namespace std;

typedef uint32_t ui;

static const ui INF = 1 << 30;

ui cost[101][101][2];

int main() {
  int n, m;
  while (cin >> n >> m, n | m) {
    fill_n(cost[0][0], sizeof(cost) / sizeof(ui), INF);
    for (int i = 1; i <= m; i++) cost[i][i][0] = cost[i][i][1] = 0;
    while (n--) {
      int a, b, c, t;
      cin >> a >> b >> c >> t;
      cost[a][b][0] = c;
      cost[b][a][0] = c;
      cost[a][b][1] = t;
      cost[b][a][1] = t;
    }

    for (int k = 1; k <= m; k++) {
      for (int i = 1; i <= m; i++) {
        for (int j = i + 1; j <= m; j++) {
          for (auto&& r : {0, 1}) {
            cost[i][j][r] = cost[j][i][r] = min(cost[i][k][r] + cost[k][j][r], cost[i][j][r]);
          }
        }
      }
    }

    int k;
    cin >> k;
    while (k--) {
      int p, q, r;
      cin >> p >> q >> r;
      cout << cost[p][q][r] << endl;
    }
  }
  return 0;
}

C++: #include <iostream>
#include <cstdio>
#include <cstdlib>
#include <time.h>
#include <math.h>
#include <vector>
#include <queue>
#include <map>
#include <set>
#include <algorithm>
#include <iterator>
#include <sstream>
#include <string>
#include <bitset>
using namespace std;
#define FOR(I,F,N) for(int I = F; I < (int)(N); I++)
#define rep(i, n) FOR(i, 0, n)
#define FIN(V) cout<<V<<endl
#define pb push_back
#define INF 1000000000
typedef pair<int, int> P;
typedef long long ll;
typedef priority_queue<int> pq;
int StrToInt(string);
string IntToStr(int);
int dx[4] = {1, -1, 0, 0};
int dy[4] = {0, 0, 1, -1};

int n, m;
int d[101][101][2];

int main(void){

	while(cin >> n >> m, n){
		fill_n(**d, 101*101*2, 1000000);

		for(int i = 0; i < n; i++){
			int from, to, t_cost, m_cost;
			cin >> from >> to >> t_cost >> m_cost;
			d[from][to][0] = m_cost;
			d[to][from][0] = m_cost;
			d[from][to][1] = t_cost;
			d[from][to][1] = t_cost;
		}
		rep(k, n){
			rep(i, n){
				rep(j, n){
					d[i][j][0] = min(d[i][j][0], d[i][k][0] + d[k][j][0]);
					d[i][j][1] = min(d[i][j][1], d[i][k][1] + d[k][j][1]);
				}
			}
		}
		int t;
		cin >> t;
		rep(i, t){
			int a, b, r;
			cin >> a >> b >> r;
			cout << d[a][b][r] << endl;
		}
	}




	return 0;
}



int StrToInt(string s){
	stringstream ss;
	ss << s;
	int val;
	ss >> val;
	return val;
}
string IntToStr(int i){
	stringstream ss;
	ss << i;
	return ss.str();
}