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
			c_matrix[b-1][a-1] = c
			t_matrix[a-1][b-1] = t
			t_matrix[b-1][a-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<cstdio>
#include<cstring>
#include<algorithm>
#include<functional>
#include<iostream>
#include<queue>
#define rep(i,a,b) for(i=a;i<b;i++)
#define F1 first.first
#define F2 first.second
#define F3 second
#define INF 2100000000
//#define long long int int
using namespace std;
typedef pair<pair<int,int>,int> P1;
typedef pair<int,int> P2;
int main(void)
{
	int i,j,k,n,m,x,s,e;
	int a,b,cos,tim,st,en,way;
	int leng[1001],kami[1002];
	P1 glid1[6000],glid2[6000];
	P2 tori;
	while(cin>>n>>m,n&&m) {
		rep(i,0,n) {
			cin>>a>>b>>cos>>tim;
			glid1[i*2].F1=a,glid1[i*2].F2=b,glid1[i*2].F3=cos;
			glid2[i*2].F1=a,glid2[i*2].F2=b,glid2[i*2].F3=tim;
			glid1[i*2+1].F1=b,glid1[i*2+1].F2=a,glid1[i*2+1].F3=cos;
			glid2[i*2+1].F1=b,glid2[i*2+1].F2=a,glid2[i*2+1].F3=tim;
		}
		sort(glid1,glid1+m*2);sort(glid2,glid2+m*2);
		kami[1]=0;
		rep(i,1,m*2) {
			if(glid1[i].F1!=glid1[i-1].F1) {
				x=glid1[i].F1;
				kami[x]=i;
			}
		}
		kami[n+1]=m*2;
		priority_queue<P2,vector<P2>,greater<P2> > que;
		cin>>k;
		rep(i,0,k) {
			cin>>st>>en>>way;
			for(j=1;j<=n;j++) leng[j]=INF;
			while(!que.empty()) que.pop();
			que.push(P2(0,st));
			while(!que.empty()) {
				tori=que.top(),que.pop();
				a=tori.first,b=tori.second;
				if(a<leng[b]) {
					leng[b]=a;
					if(b==en) break;
					s=kami[b],e=kami[b+1];
					if(way==0)rep(j,s,e) que.push(P2(a+glid1[j].F3,glid1[j].F2));
					else rep(j,s,e) que.push(P2(a+glid2[j].F3,glid2[j].F2));
				}
			}
			cout<<leng[en]<<endl;
		}
	}
	
}

C++: #include <algorithm>
#include <map>
#include <vector>
#include <iostream>
#include <sstream>
#include <cstdio>
#include <cstring>
#include <cctype>
#include <cstdlib>
#include <cmath>
#include <string>
#include <queue>
#include <stack>
#include <set>
using namespace std;

#define REP(i,n) for(int i=0; i<n; ++i)
#define IREP(it,array) for(vector<int>::iterator it=array.begin(); it!=array.end(); ++it)
#define SREP(it,array) for(vector<string>::iterator it=array.begin(); it!=array.end(); ++it)

#define MP       make_pair
#define PB       push_back
#define ALL(x)   (x).begin(),(x).end()

const int INF = 1<<29;
const double EPS = 1e-9;
double zero(double d){
  return d < EPS ? 0.0 : d;
}

typedef long long LL;
typedef pair<int,int> P;


int main()
{
  cout.setf(ios::fixed, ios::floatfield);
  cout.precision(7);

  int n,m;
  cin >> n >> m;

  vector< vector<int> > cost(m+1, vector<int>(m+1,INF)),
    time(m+1, vector<int>(m+1,INF));

  REP(i,cost.size()){
    cost[i][i] = 0;
    time[i][i] = 0;
  }

  REP(i,n){
    int a,b,c,t;
    cin >> a >> b >> c >> t;
    cost[a][b] = c;
    cost[b][a] = c;
    time[a][b] = t;
    time[b][a] = t;
  }

  int k;
  cin >> k;
  REP(_tmp,k){
    int p,q,r;
    cin >> p >> q;
    if(p==0&&q==0)
      return 0;
    cin >> r;

    vector< vector<int> > data(m+1, vector<int>(m+1,0));
    data = r ? time : cost;

    deque<bool> reached(m+1,0);
    vector<int> dis(m+1,INF);
    dis[p] = 0;

    while(true){
      int minn = -1;
      REP(i,reached.size()){
	if( ! reached[i] ){
	  if( minn==-1 || dis[minn] > dis[i] ){
	    minn = i;
	  }
	}
      }
      if( minn == q )
	break;

      reached[minn] = true;
      REP(i,data[minn].size()){
	dis[i] = min( dis[minn] + data[minn][i], dis[i] );
      }
    }

    cout << dis[q] << endl;
  }

  return 0;
}