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<iostream>
#include<vector>
using namespace std;

const int inf = 1e8;
int m,n;
//n経路の数（枝）　m駅の数（葉）
struct edge{
  int from,to,cost,time;
  edge(int from,int to,int cost,int time): from(from), to(to), cost(cost), time(time){}
};

vector<edge> es;
int shortest_path(int s,int e,int v){
  int d[m];
  for(int i = 0 ; i < n ; i ++)d[i] = inf;
  d[s] = 0 ;
  while(true){
    bool updata = false;
    for(int i = 0 ; i < n ; i ++){
      edge e = es[i];
      if(d[e.from] != inf && d[e.to]> d[e.from] + e.cost && v == 0){
	d[e.to] = d[e.from] + e.cost;
	updata = true;
      }

      if(d[e.from] != inf && d[e.to]> d[e.from] + e.time && v == 1){
	d[e.to] = d[e.from] + e.time;
	updata = true;
      }
    } 
    if(!updata) break;
  }
  return d[e];
}

int main(void){
  while(cin>>n>>m,m+n){
    es.clear();
    for(int i = 0 ; i < n ; i ++){
      int s,t,c,ti;
      cin>>s>>t>>c>>ti;
      s--; t--;
      es.push_back(edge(s,t,c,ti));
    }
    int num;
    cin>>num;
    for(int i = 0 ; i < num ;  i++){
      int s,t,v;
      cin>>s>>t>>v;
      s--; t--;
      //cout<<s <<" " << t << " " << v<<" ";
      cout<<shortest_path(s,t,v)<<endl;
    }
  }
  
    
}

C++: #include<iostream>
#include<math.h>
#include<string>
#include<vector>
#include<algorithm>
#include<queue>
using namespace std;
#define INF 1<<30

struct edge{
	int to;
	int cost;
	edge() {};
	edge(int a, int b) {
		to = a;
		cost = b;
	}
};

struct Node {
	int pos;
	int cost;
	Node() {};
	Node(int a, int b) {
		pos = a;
		cost = b;
	}
	bool operator <(const Node& rhs) const {
		return cost > rhs.cost;
	}
};

void dijkistra(int st, int TO,int V,vector<vector<edge> >& graph) {
	priority_queue<Node> q;
	vector<int> d(V);
	for (int i = 0;i < V;i++) {
		d[i] = INF;
	}
	d[st] = 0;
	q.push(Node(st, 0));
	while (!q.empty()) {
		Node s = q.top(); q.pop();
		int pos = s.pos;
		for (int i = 0;i < graph[pos].size();i++) {
			int to = graph[pos][i].to;
			int cost = graph[pos][i].cost;
			if (d[pos] + cost < d[to]) {
				d[to] = d[pos] + cost;
				q.push(Node(to, d[to]));
			}

		}
	}
	cout << d[TO] << endl;


}
int partition(int A[],int p, int r) {
	int x = A[r];
	int i = p - 1;
	for (int j = p;j < r;j++) {
		if (x >= A[j]) {
			i = i + 1;
			swap(A[i], A[j]);
		}
	}
		swap(A[i + 1], A[r]);
		return i + 1;
}
void quicksort(int A[], int p, int r) {
	if (p < r) {
		int q = partition(A, p, r);
		quicksort(A, p, q-1);
		quicksort(A, q + 1, r);
	}
}

int getNumberOfCoin(int C[],int n,int m) {
	int T[50000];
	for (int j = 0;j <= n;j++) {
		T[j] = INF;
	}
	T[0] = 0;
	for (int i = 0;i < m;i++) {
		for (int j = 0;j <= n;j++) {
			if (j - C[i] >=0  ) {
				T[j] = min(T[j], T[j - C[i]] + 1);
			}
		}
	}
	return T[n];
}
int knapsack(int w, int n,int* v,int* ww) {
	int W[101][10001];
		for (int j = 0;j <= w;j++) {
			W[0][j] = 0;
		}
	for (int i = 0;i < n;i++) {
		for (int k = 0;k < n;k++){
			for (int j = 0;j <= w;j++) {
				if (j - ww[k] < 0) {
					W[i + 1][j] = W[i][j];
				}
				if (j - ww[i] >= 0) {
					W[i + 1][j] = max(W[i][j], W[i][j - ww[k]] + v[k]);

				}
			}
		}
	}
	return W[n][w];
}
int main() {
	int line, num;
	cin >> line >> num;
	vector<vector<edge> > COST(num);
	vector<vector<edge> > TIME(num);
	for (int i = 0;i < line;i++) {
		int a, b, cost, time;
		cin >> a>>b>>cost>>time;
		COST[a-1].push_back(edge(b-1, cost));
		COST[b-1].push_back(edge(a-1, cost));
		TIME[a-1].push_back(edge(b-1, time));
		TIME[b-1].push_back(edge(a-1, time));
	}
	int k;
	cin >> k;
	for (int i = 0;i < k;i++) {
		int p, q, r;
		cin >> p >> q >> r;
		if (r == 0) {
			dijkistra(p-1, q-1, num, COST);
		}
		else if (r == 1) {
			dijkistra(p-1, q-1, num, TIME);
		}
	}
	int n1, n2;
	cin >> n1 >> n2;
	return 0;
	
}

int isPrime(int x) {
	if (x <= 1) return false;
	if (x>2 && x % 2 == 0) return false;
	for (int i = 2;i <= sqrt(x);i++) {
		if (x%i == 0) {
			return false;
		}
	}
	if (x == 2) return true;
	return true;
}

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

typedef pair<int,int> P;

#define REP(i,b,n) for(int i=b;i<n;i++)
#define rep(i,n) REP(i,0,n)
#define mp make_pair
#define pb push_back

struct edge {
  int to, cost, time;
  edge(int a, int b, int c): to(a), cost(b), time(c) {}
};

const int MAX_M = 100, INF = 10000000;
int n, m;

void solve() {
  vector<edge> E[MAX_M+1];
  rep(i,n) {
    int a, b, cost, time; cin>>a>>b>>cost>>time;
    E[a].push_back(edge(b, cost, time));
    E[b].push_back(edge(a, cost, time));
  }
  int zz; cin>>zz;
  rep(z,zz) {
    int p, q, r; cin>>p>>q>>r;
    // dijkstra
    int d[MAX_M+1];
    fill(d, d+MAX_M, INF);
    priority_queue<P, vector<P>, greater<P> > que;
    que.push(P(0, p));
    d[p] = 0;
    while (!que.empty()) {
      P p = que.top(); que.pop();
      int td = p.first, ti = p.second;
      if (d[ti] < td) continue;
      rep(i,E[ti].size()) {
        edge e = E[ti][i];
        if (r == 0) {
          if (d[e.to] > d[ti] + e.cost) {
            d[e.to] = d[ti] + e.cost;
            que.push(P(d[e.to], e.to));
          }
        } else {
          if (d[e.to] > d[ti] + e.time) {
            d[e.to] = d[ti] + e.time;
            que.push(P(d[e.to], e.to));
          }
        }
      }
    }
    cout<<d[q]<<endl;
  }
}

int main (int argc, char const* argv[]) {
  while (cin>>n>>m, n||m) {
    solve();
  }
  return 0;
}