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])
			}
		}
	}
}

C++: #include <vector>
#include <iostream>
#include <utility>
#include <algorithm>
#include <string>
#include <deque>
#include <queue>
#include <tuple>
#include <queue>
#include <functional>
#include <cmath>
#include <iomanip>
#include <map>
#include <set>
#include <numeric>
#include <unordered_map>
#include <unordered_set>
#include <complex>
#include <iterator>
#include <array>
#include <memory>
#include <stack>
#define vi vector<int>
#define vvi vector<vector<int> >
#define ll long long int
#define vl vector<ll>
#define vvl vector<vector<ll>>
#define vb vector<bool>
#define vc vector<char>
#define vs vector<string>
#define ld long double
#define INF 1e9
#define EPS 0.0000000001
#define rep(i,n) for(int i=0;i<n;i++)
#define loop(i,s,n) for(int i=s;i<n;i++)
#define all(in) in.begin(), in.end()
template<class T, class S> void cmin(T &a, const S &b) { if (a > b)a = b; }
template<class T, class S> void cmax(T &a, const S &b) { if (a < b)a = b; }
#define MAX 9999999
using namespace std;
typedef pair<int, int> pii;
typedef pair<double,double>pdd;
typedef pair<ll,ll>pll;
int main(){
    int n,m;
    while(cin>>n>>m,n+m){
        vector<vector<pii>>d(m+1,vector<pii>(m+1,pii(INF,INF)));
        for(int i=0;i<m;i++)d[i][i]=pii(0,0);
        rep(i,n){
            int a = 0,b = 0;pii hoge; cin>>a>>b>>hoge.first>>hoge.second;
            --a,--b;
            d[a][b]=hoge;
            d[b][a]=hoge;
        }
        rep(k,m)rep(i,m)rep(j,m)cmin(d[i][j].first,d[i][k].first+d[k][j].first);
        rep(k,m)rep(i,m)rep(j,m)cmin(d[i][j].second,d[i][k].second+d[k][j].second);
        int k; cin>>k;
        rep(i,k){
            int to,from,q; cin>>to>>from>>q;
            to--,from--;
            if(q)cout<<d[to][from].second<<endl;
            else cout<<d[to][from].first<<endl;
        }
    }
}

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 <cstring>
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<iostream>
#include<algorithm>
#include<climits>
using namespace std;
const int INF = INT_MAX/3;
const int MAXN = 10000;
const int TIME = 1,COST = 0;
int graph[2][MAXN][MAXN];
int n,m,a,b,c,t,k;//m:wÌAn:GbWÌ
void solve();
void init(){
  for(int i = 0;i < m;i++)
    for(int j = 0;j < m;j++)
      graph[0][i][j] =graph[0][j][i] = graph[1][j][i] = graph[1][i][j] = INF;
}


int main(){
  cin >> n >> m;
  init();
  for(int i = 0;i < n;i++){
    cin >> a >> b >> c >>t;
    graph[TIME][a-1][b-1] = graph[TIME][b-1][a-1] = t;
    graph[COST][a-1][b-1] = graph[TIME][b-1][a-1] = c;
  }

  solve();

  cin >> k;
  for(int i = 0;i < k;i++){
    cin >> a >> b >>c;
    cout << graph[c][a-1][b-1] << endl;
  }
  cout.flush();
  return 0;
}

void solve(){
  for(int k = 0;k < m;k++){
    for(int i = 0;i < m;i++){
      for(int j = 0;j < m;j++){
	graph[0][i][j] = min(graph[0][i][j],graph[0][i][k] + graph[0][k][j]);
	graph[1][i][j] = min(graph[1][i][j],graph[1][i][k] + graph[1][k][j]);
      }
    }
  }
}