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 "bits/stdc++.h"

using namespace std;

typedef vector<int> vi;
typedef pair<int,int> pii;
typedef long long ll;

#define dump(x)  cerr << #x << " = " << (x) << endl
#define rep(i,n) for(ll i=0;i<(ll)(n);i++)
#define all(a)  (a).begin(),(a).end()
#define pb push_back

int cost[200][200];
int tim[200][200];


int main(){
    int n,m;
    while(cin>>n>>m){
        if(n==0&&m==0)break;
        rep(i,200)rep(j,200){
            cost[i][j]=999999999;
            tim[i][j]=999999999;
        }
        rep(i,n){
            int a,b,c,d;
            cin>>a>>b>>c>>d;
            a--,b--;
            cost[a][b]=cost[b][a]=c;
            tim[a][b]=tim[b][a]=d;
        }
        
        rep(k,m){
            rep(i,m){
                rep(j,m){
                    cost[i][j]=min(cost[i][j],cost[i][k]+cost[k][j]);
                    tim[i][j]=min(tim[i][j],tim[i][k]+tim[k][j]);
                }
            }
        }
        int x;
        cin>>x;
        rep(i,x){
            int a,b,c;
            cin>>a>>b>>c;
            a--,b--;
            if(c==0){
                cout<<cost[a][b]<<endl;
            }else cout<<tim[a][b]<<endl;
        }
    }
}

C++: #include<iostream>
#include<queue>
#include<vector>
#include<map>
using namespace std;
typedef pair<int,int> P;
typedef struct{
	int next;
	int cost[2];
}edge;

int n,m;
vector<edge> mapp[111];
int bfs(int now,int goal,int k);

int main(){
	while(1){
		cin >> n >> m;
		if(n == 0 && m == 0) break;
		for(int i=0;i<m+1;i++){
			mapp[i].clear();
		}
		for(int i=0;i<n;i++){
			int a,b,cost,tim;
			cin >> a >> b >> cost >> tim;
			edge x;
			x.next = b; x.cost[0] = cost; x.cost[1] = tim;
			mapp[a].push_back(x);
		}
		int k;
		cin >> k;
		int ans;
		for(int i=0;i<k;i++){
			int p,q,r;
			cin >> p >> q >> r;
			if(r == 0) ans = bfs(p,q,r);
			else if(r == 1) ans = bfs(p,q,r);
			cout << ans << endl;
		}
	}
}

int bfs(int now,int goal,int k){
	priority_queue<P, vector<P>,greater<P> > que;
	que.push(P(0,now));
	while(!que.empty()){
		P p = que.top(); que.pop();
		int no = p.second;
		int co = p.first;
		if(no == goal) return co;
		int len=mapp[no].size();
		for(int i=0;i<len;i++){
			edge x = mapp[no][i];
			que.push(P(co+x.cost[k],x.next));
		}
	}
	return 0;
}