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<bits/stdc++.h>
#define ll long long int
#define FOR(i,a,b) for(ll i=(ll)(a);i<(ll)(b);i++)
#define REP(i,n) FOR(i,0,n)
#define REP1(i,n) FOR(i,1,n)
#define MIN(a, b) ((a)<(b)?(a):(b))
#define MAX(a, b) ((a)<(b)?(a):(b))
#define INF 10e6
using namespace std;
 /*temp*/

int main(){
    int n, m, l;
    while(cin>>m>>n,n){
        int cost[n][n],time[n][n];
        // set table
        REP(i,n){
            REP(j,n){
                cost[i][j]=time[i][j]=INF;
            }
            cost[i][i]=time[i][i]=0;
        }
        // read
        REP(i,n){
            int a,b,c,t;
            a--;
            b--;
            cost[a][b]=cost[b][a]=MIN(c,cost[a][b]);
            time[a][b]=time[b][a]=MIN(t,time[a][b]);
        }
        // Warshall???Floyd Algorithm
        REP(a,n){
            REP(b,a+1){
                REP(k,n){
                    cost[a][b]=cost[b][a]=MIN(cost[a][b],cost[a][k]+cost[k][b]);
                    time[a][b]=time[b][a]=MIN(time[a][b],time[a][k]+time[k][b]);
                }
            }
        }
        // 
        int q;
        cin>>q;
        REP(i,q){
            int s,d,type;
            cin>>s>>d>>type;
            s--;
            d--;
            cout<<type==0?cost[s][d]:time[s][d]<<'\n';
        }
    }
    return 0;
}

C++: #include<cstdio>
#include<iostream>
#include<queue>

#define NMAX 3000
#define MMAX 100
#define INF (1000*MMAX+100)*1000
using namespace std;

int main(void){

	int n,m;
	int a[NMAX],b[NMAX],cost[2][NMAX];
	int k;
	int p,q,r,flag;
	int node[MMAX];

	while(1){
		cin>>n>>m;
		if(n==0||m==0) break;
		for(int i=0;i<n;i++){
			cin>>a[i]>>b[i]>>cost[0][i]>>cost[1][i];
		}
		cin>>k;
		for(int i=0;i<k;i++){
			cin>>p>>q>>r;

			for(int i=0;i<MMAX;i++) node[i]=INF;
			node[p]=0;
			flag=1;
			while(flag){
				flag=0;
				for(int j=0;j<n;j++){
					if(node[a[j]]!=INF){
						if(node[b[j]]>node[a[j]]+cost[r][j]){
							node[b[j]]=node[a[j]]+cost[r][j];
							flag=1;
						}
					}
					if(node[b[j]]!=INF){
						if(node[a[j]]>node[b[j]]+cost[r][j]){
							node[a[j]]=node[b[j]]+cost[r][j];
							flag=1;
						}
					}
				}
			}
			
			cout<<node[q]<<endl;
		}
	}

	return 0;
}

C++: #include <iostream>
#include <algorithm>
#define MAX_M 100
#define INF 1e9
using namespace std;

int dp_cost[MAX_M][MAX_M];
int dp_time[MAX_M][MAX_M];
int m;

void warshall_froyd(){
  for(int k=0;k<m;k++){
    for(int i=0;i<m;i++){
      for(int j=0;j<m;j++){
        dp_cost[i][j] = min(dp_cost[i][j], dp_cost[i][k] + dp_cost[k][j]);
        dp_time[i][j] = min(dp_time[i][j], dp_time[i][k] + dp_time[k][j]);
      }
    }
  }
}

int main(){
  int n;
  
  while(cin >> n >> m){
    if(n == 0 && m == 0) break;
    for(int i=0;i<m;i++){
      for(int j=0;j<m;j++){
        dp_time[i][j] = (i==j ? 0 : INF);
        dp_cost[i][j] = (i==j ? 0 : INF);
      }
    }
    
    for(int i=0;i<n;i++){
      int a,b,cost,time;
      cin >> a >> b >> cost >> time;
      a--;
      b--;
      dp_cost[a][b] = cost; dp_cost[b][a] = cost;
      dp_time[a][b] = time; dp_time[b][a] = time;
    }
    
    warshall_froyd();
    
    int k,p,q,r;
    cin >> k;
    for(int i=0;i<k;i++){
      cin >> p >> q >> r;
      p--; q--;
      cout << (r == 0 ? dp_cost[p][q] : dp_time[p][q]) << endl;
    }
  }
  return 0;
}