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>
using namespace std;
#define FOR(i,k,n) for(int i = (k); i < (n); i++)
#define REP(i,n) FOR(i,0,n)
#define INF 114514810
#define MOD 1000000007
#define ALL(a) (a).begin(),(a).end()
#define pb(x) push_back(x)
#define ms(m,v) memset(m,v,sizeof(m))
#define D10  fixed<<setprecision(10) 
typedef vector<int> vi;
typedef vector<string> vs;
typedef pair<int, int> P;
typedef long long ll;

int main()
{
	int n, m;
	while (cin >> n >> m, n)
	{
		int cost[105][105]; int time[105][105];
		REP(i, m)REP(j, m)
		{
			cost[i][j] = (i == j ? 0 : INF);
			time[i][j] = (i == j ? 0 : INF);
		}
		int a, b, c, d;
		REP(i, n)
		{
			cin >> a >> b >> c >> d;
			a--; b--;
			cost[a][b] = cost[b][a] = c;
			time[a][b] = time[b][a] = d;
		}
		int k; cin >> k;
		int p, q, r;
		REP(i, k)
		{
			cin >> p >> q >> r;
			p--; q--;
			int d[105];
			fill(d, d + m, INF);
			d[p] = 0;
			bool used[105] = {};
			while (1)
			{
				int v = -1;
				REP(i, m) if (!used[i] && (v == -1 || d[i] < d[v])) v = i;
				if (v == -1) break;
				used[v] = true;
				REP(i, m) d[i] = min(d[i], d[v] + (r ? time[v][i] : cost[v][i]));
			}

			cout << d[q] << endl;
		}
	}
	return 0;
}

C++: #include <iostream>
#include <algorithm>
#define MAX 1000
#define INF 999999

using namespace std;

int COST[MAX + 1][MAX + 1];
int TIME[MAX + 1][MAX + 1];
int v[MAX + 1];
bool visit[MAX + 1];
int n,m,k,p,q,r,ti,co;
int from,too;
int MI,mi;

int get_time(void){ // ダイクストラ法

  for( int i = 0 ; i <= MAX ; i++ ){ // 初期化
    visit[i] = false;
    v[i] = INF;
  }


  v[p] = 0; // 最初の位置を0にする

  while(1){

    MI = INF;

    for( int i = 1 ; i <= m ; i++ ){ // 訪れていない最小の添字を探す
      if( !visit[i] && v[i] < MI ){
	MI = i;
	mi = v[i];
      }
    }

    if( MI == INF ) break;
    visit[MI] = true; // 訪れたことにする

    for( int i = 1 ; i <= m ; i++ ){
      if( TIME[MI][i] + v[MI] < v[i] ){
	v[i] = TIME[MI][i] + v[MI];
      }
    }
  }
  return v[q];
}

int get_cost(void){

  for( int i = 0 ; i <= MAX ; i++ ){
    v[i] = INF;
    visit[i] = false;
  }

  v[p] = 0; 

  while(1){

    MI = INF;
    for( int i = 1 ; i <= m ; i++ ){
      if( !visit[i] && v[i] < MI ){
	MI = i;
	mi = v[i];
      }
    }

    if( MI == INF ) break;
    visit[MI] = true;

    for( int i = 1 ; i <= m ; i++ ){
      if( COST[MI][i] + v[MI] < v[i] ){
	v[i] = COST[MI][i] + v[MI];
      }
    }
  }
  return v[q];
}



int main(void){

  while( cin >> n >> m , n || m ){

    for( int i = 0 ; i <= MAX ; i++ ){
      for( int j = 0 ; j <= MAX ; j++ ){
	TIME[i][j] = INF;
	COST[i][j] = INF;
      }
    }

    for( int i = 0 ; i < n ; i++ ){
      cin >> from >> too >> co >> ti;
      COST[from][too] = COST[too][from] = co;
      TIME[from][too] = TIME[too][from] = ti;
    }

    cin >> k; // 問い合わせの数

    for( int i = 0 ; i < k ; i++ ){
      cin >> p >> q >> r;

      switch(r){
      case 0: // 最小金額
	cout << get_cost() << endl;
	break;
      case 1: // 最小時間
	cout << get_time() << endl;
      }

    }

  }
  return 0;
}

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;
}