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++: #define NODE 0
#define WEIGHT 1
#define COST_IDX 0
#define TIME_IDX 1
#define P_IDX 0
#define Q_IDX 1
#define R_IDX 2
#include <iostream>
#include <queue>
#include <vector>
using namespace std;

int n, m, k;
int weights[101][101][2];
int min_w[101][101][2];
int requests[200][3];

bool read_input() {
  cin >> n >> m;
  if (n*m == 0) 
    return false;
  memset(weights, 0, sizeof(int)*101*101*2);
  memset(min_w, 0, sizeof(int)*101*101*2);
  for (int i = 0; i < n; i++) {
    int a, b, c, t;
    cin >> a >> b >> c >> t;
    weights[a][b][COST_IDX] = weights[b][a][COST_IDX] = c;
    weights[a][b][TIME_IDX] = weights[b][a][TIME_IDX] = t;
  }
  cin >> k;
  for (int i = 0; i < k; i++) {
    cin >> requests[i][P_IDX] >> requests[i][Q_IDX] >> requests[i][R_IDX];
  }
  return true;
}

int resolve_request(int i_th) {
  int p, q, r;
  p = requests[i_th][P_IDX];
  q = requests[i_th][Q_IDX];
  r = requests[i_th][R_IDX];

  if (min_w[p][q][r])
    return min_w[p][q][r];

  int weight_sum_map[101];
  int in_queue[101] = {}; // set all to 0
  memset(weight_sum_map, -1, sizeof(int)*101);
  
  /* starting node has weight_sum of 0 */
  weight_sum_map[p] = 0;
  in_queue[p] = 1;
  int current_node = p; // first in queue is p

  while (current_node != q) {
    int weight_sum = weight_sum_map[current_node];
    in_queue[current_node] = 0;
    min_w[p][current_node][r] = weight_sum;
    
    for (int i = 1; i < 101; i++) {
      if (!weights[current_node][i][r]) 
	continue;
      int adj_node = i;
      int w = weights[current_node][adj_node][r];
      int new_weight_sum =  weight_sum + w;
      if (weight_sum_map[adj_node] == -1 || new_weight_sum < weight_sum_map[adj_node]) {
	weight_sum_map[adj_node] = new_weight_sum;
	in_queue[adj_node] = 1;
      }
    }
    
    int min_sum = -1;
    for (int i = 1; i < 101; i++) {
      if (in_queue[i] && (min_sum == -1 || weight_sum_map[i] < min_sum)) {
	min_sum = weight_sum_map[i];
	current_node = i;
      }
    }
  }
  return weight_sum_map[q];
}

void solve() {
  for (int i = 0; i < k; i++)
    cout << resolve_request(i) << endl;
}

int main() {
  while(read_input()) {
    solve();
  }
  return 0;
}

C++: #include <bits/stdc++.h>

using namespace std;

#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
#define fi first
#define se second

template<typename A, typename B> inline bool chmax(A &a, B b) { if (a<b) { a=b; return 1; } return 0; }
template<typename A, typename B> inline bool chmin(A &a, B b) { if (a>b) { a=b; return 1; } return 0; }

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<int, pll> pip;
const ll INF = 1ll<<29;
const ll MOD = 1000000007;
const double EPS  = 1e-9;

int n, m;
int d[2][100][100]; // cost time

int main() {
	while (cin >> n >> m, n | m) {
		fill(d[0][0], d[2][0], INF);
		
		REP(i, n) {
			int a, b, c, t;
			scanf("%d %d %d %d", &a, &b, &c, &t);
			a--; b--;
			chmin(d[0][a][b], c);
			chmin(d[0][b][a], c);
			chmin(d[1][a][b], t);
			chmin(d[1][b][a], t);
		}
		
		REP(s, 2) {
			REP(k, m) REP(i, m) REP(j, m) chmin(d[s][i][j], d[s][i][k] + d[s][k][j]);
		}
		
		int k;
		scanf("%d", &k);
		while (k--) {
			int p, q, r;
			scanf("%d %d %d", &p, &q, &r);
			printf("%d\n", d[r][p - 1][q - 1]);
		}
	}
	return 0;
}

C++: #include<iostream>
#include<string>
#include<algorithm>
#include<stack>
#include<queue>
#include<map>
#include<cstdio>
#include<cstring>
#include<cmath>
using namespace std;

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

const int MAXN = 301, MAXM = 101;
const int INF = 1000000 ;
const int TIME = 1, COST = 0;

int cost[2][MAXM][MAXM] = {};
int d[MAXM] = {};
bool used[MAXM] = {};

int n, m ,a, b, c, t, k;

int p, q, r;

int main()
{
    while(cin >> n >> m && n)
    {
        memset(cost, INF, sizeof(cost));

        REP(n)
        {
            cin >> a >> b >> c >> t;
            a--;
            b--;
            cost[COST][a][b] = cost[COST][b][a] = c;
            cost[TIME][a][b] = cost[TIME][b][a] = t;
        }
        cin >> k;

        rep(s,k)
        {
            cin >> p >> q >> r;
            p--;
            q--;
            memset(d, INF, sizeof(d));
            memset(used, false, sizeof(used));
            d[p] = 0;

            while(true)
            {
                int v = -1;
                rep(i,m)if(!used[i] && (v==-1 || d[i] < d[v])) v = i;
    
                if(v == -1) break;
                used[v] = true;
                rep(i,m)d[i] = min(d[i], d[v] + cost[r][v][i]);
            }
            cout << d[q] << endl;
        }
    }
    return 0;
}