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 <vector>
#include <queue>
#define INF (int)1e9

int common_part(int m, int p, int q, std::vector<std::vector<std::pair<int, int> > > v); 
int bellman_ford(std::vector<std::vector<std::pair<int, int> > > v, std::vector<int> rvec); 

int main(void) {
    int n;
    int m;

    int a;
    int b;
    int cost;
    int time;

    int k;

    int p;
    int q;
    int r;

    int res;

    while (true) {
        std::cin >> n >> m;
        if (n == 0 && m == 0) {
            break; 
        }

        std::vector<std::vector<std::pair<int, int> > > vcost(m);
        std::vector<std::vector<std::pair<int, int> > > vtime(m);

        for (int i = 0; i < n; i++) {
            std::cin >> a >> b >> cost >> time;
            --a;
            --b;
            vcost[a].push_back(std::make_pair(cost, b));
            vcost[b].push_back(std::make_pair(cost, a));
            vtime[a].push_back(std::make_pair(time, b));
            vtime[b].push_back(std::make_pair(time, a));
        }

        std::cin >> k;

        for (int i = 0; i < k; i++) {
            std::cin >> p >> q >> r;
            --p;
            --q;

            // Bellman Ford or Dijkstra
            if (r == 0) {
                res = common_part(m, p, q, vcost);
            } else {
                res = common_part(m, p, q, vtime);
            }
            std::cout << res << std::endl;
        }
    }
    return 0;
}

void bellman_ford(int m, std::vector<std::vector<std::pair<int, int> > > &v, std::vector<int> &rvec, bool &flag) {
    int value;
    int target;

    for (int i = 0; i < m; i++) {
        for (int j = 0; j < v[i].size(); j++) {
            value = v[i][j].first;
            target = v[i][j].second;
            if (rvec[target] > rvec[i] + value) {
                rvec[target] = rvec[i] + value;
                flag = true;
            }
        }
    }
    return;
} 

int common_part(int m, int p, int q, std::vector<std::vector<std::pair<int, int> > > v) {
    std::vector<int> rvec(m, INF);
    bool flag;
    rvec[p] = 0;

    do{
        flag = false;
        bellman_ford(m, v, rvec, flag);

    } while(flag);

    return rvec[q];
}

C++: #include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

struct Edge{
    int from,to,cost;
    Edge(int from,int to,int cost)
        : from(from),to(to),cost(cost) {};
};

const int INF = 1 << 30;
// s:始点,dist:距離,prev:最短経路木
bool bellman(vector<vector<Edge> > graph,int s,vector<int> &dist,vector<int> &prev){
    int n = graph.size();
    for(int i=0;i<n;i++) dist[i] = INF;
    dist[s] = 0;
    for(int i=0;i<n;i++) prev[i] = -1;

    bool neg_cycle = false;
    for(int i=0;i<n;i++){
        for(int j=0;j<n;j++){
            for(int k=0;k<graph[j].size();k++){
                Edge e = graph[j][k];
                if(dist[e.to] > dist[e.from] + e.cost){
                    dist[e.to] = dist[e.from] + e.cost;
                    prev[e.to] = e.from;
                    if(i == n-1){
                        dist[e.to] = -INF;
                        neg_cycle = true;
                    }
                }
            }
        }
    }
    return !neg_cycle;
}

int main(){
    while(true){
        int n,m;
        cin >> n >> m;
        if(n == 0 and m == 0) break;
        vector<vector<Edge> > C(m);
        vector<vector<Edge> > T(m);

        for(int i=0;i<n;i++){
            int a,b,cost,time;
            cin >> a >> b >> cost >> time;
            a--;b--;
            C[a].push_back(Edge(a,b,cost));
            C[b].push_back(Edge(b,a,cost));
            T[a].push_back(Edge(a,b,time));
            T[b].push_back(Edge(b,a,time));
        }
        int k;
        cin >> k;
        for(int i=0;i<k;i++){
            int p,q,r;
            cin >> p >> q >> r;
            p--,q--;
            vector<int> dist(m);
            vector<int> prev(m);
            if(r == 0){
                bellman(C,p,dist,prev);
            }else{
                bellman(T,p,dist,prev);
            }
            cout << dist[q] << endl;
        }
    }
    return 0;
}

C++: #include <iostream>
#include <vector>
#include <queue>
#include <utility>
#include <algorithm>
using namespace std;

struct edge{
  int to,cost;
  edge(){}
  edge(int to,int cost):to(to),cost(cost){}
};
typedef pair<int,int> P;
const int INF=11111;

vector<edge> G_cost[3000];
vector<edge> G_time[3000];
int d[101];

int main(void){
  int n,m,a,b,c,t;
  int k,p,q,r;
  priority_queue<P,vector<P>,greater<P> > que;
  while(cin>>n>>m,!(n==0&&m==0)){
    for(int i=0;i<3000;i++){
      G_cost[i].clear();
      G_time[i].clear();
    }
    for(int i=0;i<n;i++){
      cin>>a>>b>>c>>t;
      G_cost[a].push_back(edge(b,c));
      G_cost[b].push_back(edge(a,c));
      G_time[a].push_back(edge(b,t));
      G_time[b].push_back(edge(a,t));
    }
    cin>>k;
    for(int i=0;i<k;i++){
      cin>>p>>q>>r;
      fill(d,d+m+1,INF);
      d[p]=0;
      que.push(P(0,p));
      if(r==0){
	while(!que.empty()){
	  P p=que.top(); que.pop();
	  if(d[p.second]<p.first)continue;
	  for(int j=0;j<G_cost[p.second].size();j++){
	    edge e=G_cost[p.second][j];
	    if(d[e.to]>d[p.second]+e.cost){
	      d[e.to]=d[p.second]+e.cost;
	      que.push(P(d[e.to],e.to));
	    }
	  }
	}
	cout<<d[q]<<endl;
      }
      if(r==1){
	while(!que.empty()){
	  P p=que.top(); que.pop();
	  if(d[p.second]<p.first)continue;
	  for(int j=0;j<G_time[p.second].size();j++){
	    edge e=G_time[p.second][j];
	    if(d[e.to]>d[p.second]+e.cost){
	      d[e.to]=d[p.second]+e.cost;
	      que.push(P(d[e.to],e.to));
	    }
	  }
	}
	cout<<d[q]<<endl;
      }
    }
  }
  return 0;
}