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<queue>
#include<cstdio>
#include<algorithm>

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

using namespace std;

template<class T>
class d_heap{
	static const int N_MAX=3000; // !!
	int n,d;
	T a[N_MAX];
public:
	d_heap(int d):n(0),d(d){}
	const T &find_min()const{ return a[0]; }
	void insert(const T &x){
		int u=n++;
		a[u]=x;
		while(u!=0 && a[(u-1)/d]>a[u]) swap(a[(u-1)/d],a[u]), u=(u-1)/d;
	}
	void delete_min(){
		a[0]=a[--n];
		for(int u=0;;){
			int v=u;
			for(int w=d*u+1;w<=d*u+d;w++) if(w<n && a[v]>a[w]) v=w;
			if(v==u) break;
			swap(a[v],a[u]);
			u=v;
		}
	}
	bool empty()const{ return n==0; }
	int size()const{ return n; }
};

#define define_heap d_heap< pair<int,int> > H(30);

const int INF=1<<29;

struct edge{ int v,cost1,cost2; };

int main(){
	for(int m,n;scanf("%d%d",&m,&n),n;){
		vector<edge> G[100];
		rep(i,m){
			int u,v,cost1,cost2; scanf("%d%d%d%d",&u,&v,&cost1,&cost2); u--; v--;
			G[u].push_back((edge){v,cost1,cost2});
			G[v].push_back((edge){u,cost1,cost2});
		}

		int q; scanf("%d",&q);
		while(q--){
			int s,t,type; scanf("%d%d%d",&s,&t,&type); s--; t--;

			int d[100];
			rep(u,n) d[u]=(u==s?0:INF);
			define_heap;
			H.insert(make_pair(0,s));
			while(!H.empty()){
				int d_now=H.find_min().first,u=H.find_min().second;
				H.delete_min();

				if(d[u]<d_now) continue;

				rep(i,G[u].size()){
					const edge &e=G[u][i];
					int d2=d_now+(type==0?e.cost1:e.cost2);
					if(d[e.v]>d2){
						d[e.v]=d2;
						H.insert(make_pair(d2,e.v));
					}
				}
			}

			printf("%d\n",d[t]);
		}
	}

	return 0;
}

C++: #include <iostream>
#include <cstring>
using namespace std;

const int INF = 1000000;
const int MAX_V = 101;
const int MAX_E = 20000;

int cost[MAX_V][MAX_V];
int tttt[MAX_V][MAX_V];
int d[MAX_V];
bool used[MAX_V];
int V;

int n,m;

void dijkstra(int s,bool r){
    fill(d,d+m,INF);
    memset(used,false,sizeof(used));
    d[s]=0;
    while(1){
        int v=-1;
        for(int u=0;u<m;u++){
            if(used[u]) continue;
            if(v==-1||d[u]<d[v]){
                v=u;
            }
        }
        if(v==-1) break;
        used[v]=true;
        for(int u=0;u<m;u++){
            int c;
            if(r) c=cost[u][v];
            else c=tttt[u][v];
            d[u]=min(d[u],d[v]+c);
        }
    }
}
int main(){
    while(cin >> n >> m,n+m){
        for(int i=0;i<m+1; i++){
            for(int j=0; j<m; j++){
                cost[i][j]=INF;
                tttt[i][j]=INF;
            }
        }
        for (int i = 0; i < m+1; ++i) {
            cost[i][i]=0;
            tttt[i][i]=0;
        }
        for (int i = 0; i < n; ++i) {
            int to,from,c,t;
            cin >> to>>from>>c>>t;
            to--; from--;
            cost[to][from]=c;
            cost[from][to]=c;
            tttt[to][from]=t;
            tttt[from][to]=t;
        }
        int k; cin>>k;
        for (int i = 0; i < k; ++i) {
            int p,q,r;
            cin>>p>>q>>r;
            p--; q--;
            dijkstra(p,!r);
            cout<<d[q]<<endl;
        }
    }
}

C++: #include <cstdio>
#include <vector>
#include <queue>
#include <functional>

using namespace std;

#define fst first
#define scd second
#define PB push_back
#define MP make_pair
#define rep(i,x) for(int i=0;i<(x);++i)

typedef pair<int, int> pii;

const int inf = 1e9;

struct edge {
	int to, cost, time;
	edge(int to0,int cost0,int time0) {
		to = to0; cost = cost0; time = time0;
	};
};

int N, M;

vector<edge> G[100];
int d[100];

void dijkstra(int s, int mode)
{
	priority_queue<pii, vector<pii>, greater<pii> > q;

	fill(d, d + M, inf);
	d[s] = 0;

	q.push(MP(0, s));

	while (q.size()) {
		pii p = q.top(); q.pop();
		int v = p.scd;
		rep(u, G[v].size()) {
			edge e = G[v][u];
			int a = mode == 0 ? e.cost : e.time;
			if (d[e.to] > d[v] + a) {
				d[e.to] = d[v] + a;
				q.push(MP(d[e.to], e.to));
			}
		}
	}
}

int main()
{
	while (scanf("%d %d", &N, &M), N || M) {
		rep(i, M) G[i].clear();

		rep(i, N) {
			int a, b, cost, time; scanf("%d %d %d %d", &a, &b, &cost, &time); a--; b--;
			G[a].PB(edge(b, cost, time));
			G[b].PB(edge(a, cost, time));
		}

		int K; scanf("%d", &K);

		rep(i, K) {
			int p, q, r; scanf("%d %d %d", &p, &q, &r); p--; q--;
			dijkstra(p, r);
			printf("%d\n", d[q]);
		}
	}
}