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 <iostream>
#include <queue>
using namespace std;
struct Line{
        int a;
        int b;
        int cost;
        int time;
};
int Min(int x,int y){
        return x<y?x:y;
}
#define Max 2000000000
int main(){
        int N,M;
        while(true){
                Line lines[3000];
                cin >> N >>M;
                if(N+M==0)      break;
                for(int i=0 ; i<N ; i++ ){
                        cin >> lines[i].a >> lines[i].b ;
                        cin >> lines[i].cost >> lines[i].time;
                }
                int K;
                cin >> K;
                for(int i=0 ; i<K ; i++ ){
                        int to,from,r;
                        cin >> from >> to>>r;
                        queue <int> circle;
                        circle.push(from);
                        int dp[3000];
                        for(int i=0 ; i<=M ; i++ )
                                dp[i]=Max;
                        dp[from]=0;
                        while(circle.size()!=0){
                                int now=circle.front();
                                for(int i=0 ; i<N ; i++ ){
                                        if(now==lines[i].a){
                                                int next=lines[i].b;
                                                if(!r)
                                                        dp[next]=Min(dp[next],dp[now]+lines[i].cost);
                                                else
                                                        dp[next]=Min(dp[next],dp[now]+lines[i].time);
                                                circle.push(lines[i].b);
                                        }
                                }
                                circle.pop();
                        }
                        cout << dp[to] << endl;
                }
        }
        return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
typedef struct E{
  int to,cost,tim;
}edge;
vector<vector<edge> >root(310);
int d[2][301];
void dijkstraco(int s){
  priority_queue<pair<int,int>,vector<pair<int,int> >,greater<pair<int,int> > >que;
  d[0][s] = 0;
  que.push(pair<int,int>(0,s));
  while(!que.empty()){
    pair<int,int> p=que.top();que.pop();
    int v = p.second;
    if(d[0][v]<p.first)continue;
    for(int j=0;j<root[v].size();j++){
      edge t = root[v][j];
      if(d[0][t.to]>d[0][v]+t.cost){
	d[0][t.to]=d[0][v]+t.cost;
	que.push(pair<int,int>(d[0][t.to],t.to));
      }
    }
  }
}
void dijkstrati(int s){
  priority_queue<pair<int,int>,vector<pair<int,int> >,greater<pair<int,int> > >que;
  d[1][s] = 0;
  que.push(pair<int,int>(0,s));
  while(!que.empty()){
    pair<int,int> p=que.top();que.pop();
    int v = p.second;
    if(d[1][v]<p.first)continue;
    for(int j=0;j<root[v].size();j++){
      edge t = root[v][j];
      if(d[1][t.to]>d[1][v]+t.tim){
	d[1][t.to]=d[1][v]+t.tim;
	que.push(pair<int,int>(d[1][t.to],t.to));
      }
    }
  }
}
int main(){
  int n,m;
  while(cin>>n>>m,n+m!=0){
    for(int j=0;j<2;j++){
      for(int a=0;a<301;a++)
	d[j][a]=1000000000;
    }
    for(int i=0;i<301;i++)
      root[i].clear();
    for(int i=0;i<n;i++){
      int f;cin>>f;
      edge e;cin>>e.to>>e.cost>>e.tim;
      root[f].push_back(e);
      int tmp=f;
      f=e.to;
      e.to=tmp;
      root[f].push_back(e);
    }
    int k;cin>>k;
    for(int i=0;i<k;i++){
      int p,q,r;cin>>p>>q>>r;
      if(r==0)
	dijkstraco(p);
      else
	dijkstrati(p);
      cout<<d[r][q]<<endl;
    for(int j=0;j<2;j++){
      for(int a=0;a<301;a++)
	d[j][a]=1000000000;
    }
    }
  }
  return 0;
}