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 <cctype>
#include <algorithm>
#include <vector>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <utility>
#include <string>
#include <functional>
#include <cctype>
#include <cstring>
#include <cstdio>
#include <cstdlib>
#include <cmath>
typedef long long ll;
const int INF = 100000000, mod = 1000000007;
const ll LLINF = 1LL << 50;
using namespace std;

struct edge { int to, cost, time; };
typedef pair<int, int> P;
vector<edge> G[105];
int n, m, k, cost[105], time[105];

void dijkstra(int s) {
    priority_queue<P, vector<P>, greater<P>> costque, timeque;
    fill(cost, cost + m + 1, INF);
    fill(time, time + m + 1, INF);
    cost[s] = 0;
    time[s] = 0;
    costque.push(P(s, 0));
    timeque.push(P(s, 0));

    while (!costque.empty()) {
        P p = costque.top();
        costque.pop();
        int v = p.first;
        if (cost[v] < p.second) continue;
        for (int i = 0; i < G[v].size(); i++) {
            edge e = G[v][i];
            if (cost[e.to] > cost[v] + e.cost) {
                cost[e.to] = cost[v] + e.cost;
                costque.push(P(e.to, cost[e.to]));
            }
        }
    }
    while (!timeque.empty()) {
        P p = timeque.top();
        timeque.pop();
        int v = p.first;
        if (time[v] < p.second) continue;
        for (int i = 0; i < G[v].size(); i++) {
            edge e = G[v][i];
            if (time[e.to] > time[v] + e.time) {
                time[e.to] = time[v] + e.time;
                timeque.push(P(e.to, time[e.to]));
            }
        }
    }
}

int main() {
    while (1) {
        cin >> n >> m;
        if (n == 0&&m == 0) break;
        for (int i = 0; i < n; i++) {
            int a, b, c, t;
            cin >> a >> b >> c >> t;
            edge tmp = { b,c,t };
            G[a].push_back(tmp);
        }
        cin >> k;
        for (int i = 0; i < k; i++) {
            int p, q, r;
            cin >> p >> q >> r;
            dijkstra(p);
            if (r == 0) cout << cost[q] << endl;
            else cout << time[q] << endl;
        }
    }
    return 0;
}

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 requests[200][3];

bool read_input() {
  cin >> n >> m;
  if (n*m == 0) 
    return false;
  memset(weights, 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];
  
  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;
    
    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 <cstdio>
using namespace std;

#define rep(i,a) for(int i = 0 ; i < a ; i ++)
#define loop(i,a,b) for(int i = a ; i < b ; i ++)

int N,M;
int maze[100][100],tim[100][100];
int main(void){
	while(cin>>N>>M,N+M){
		rep(i,M)rep(j,M)maze[i][j] = (1<<20),tim[i][j] = (1<<20);
		while(N--){
			int a,b,c,t;
			cin>>a>>b>>c>>t;
			maze[--a][--b] = c;
			tim[a][b] = t;
		}
		rep(k,M){
			rep(i,M){
				rep(j,M){
					if(maze[i][j] > maze[i][k] + maze[k][j]){
						// update
						maze[i][j] = maze[i][k] + maze[k][j];
						tim[i][j] = min(tim[i][j],tim[i][k] + tim[k][j]);
					} 
				}
			}
		}
		//rep(i,M)rep(j,M)cout<<tim[i][j]<<(j==M-1?'\n':' ');
		cin>>N;
		while(N--){
			int a,b,t;
			cin>>a>>b>>t;
			cout<<(t?tim[--a][--b]:maze[--a][--b])<<endl;
		}
	}
}