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 <bits/stdc++.h>
using namespace std ;

#define pb(n) push_back(n)
#define fi first
#define se second
#define all(r) (r).begin(),(r).end()
#define gsort(st,en) sort((st),(en),greater<int>())
#define vmax(ary) *max_element(all(ary))
#define vmin(ary) *min_element(all(ary))
#define debug(x) cout<<#x<<": "<<x<<endl
#define fcout(n) cout<<fixed<<setprecision((n))
#define scout(n) cout<<setw(n)
#define vary(type,name,size,init) vector< type> name(size,init)

#define rep(i,n) for(int i = 0; i < (int)(n);++i)
#define REP(i,a,b) for(int i = (a);i < (int)(b);++i)
#define repi(it,array) for(auto it = array.begin(),end = array.end(); it != end;++it)
#define repa(n,array) for(auto &n :(array))

using ll = long long;
using vi = vector<int>;
using vl = vector<ll>;
using dict = map<string,int>;
using pii = pair<int,int> ;

const int mod = 1000000007;
constexpr int imax = ((1<<30)-1)*2+1 ;
constexpr int inf = 100000000;
constexpr double PI = acos(-1.0) ;
double eps = 1e-10 ;
const int dy[] = {-1,0,1,0};
const int dx[] = {0,-1,0,1};

inline bool value(int x,int y,int w,int h){
  return (x >= 0 && x < w && y >= 0 && y < h);
}

template<typename T>
void Unique(vector<T> &v){
  sort(all(v));
  v.erase(unique(all(v)),v.end());
}

template<typename T>
T ston(string& str, T n){
  istringstream sin(str) ;
  T num ;
  sin >> num ;
  return num ;
}

void Ans(bool f){
  if(f) cout << "YES"<<endl;
  else cout << "NO"<<endl;
}

struct Edge{
  int to;
  long long cost;
};

struct NODE{
  int pos;
  long long cost;
};
bool operator < (const NODE &a,const NODE &b){
  return a.cost > b.cost;
}

int N;
const ll INF = 1e15;
vector<ll> dijkstra(vector<Edge> g[100000], int s){
  priority_queue<NODE> Q;
  Q.push({s,0});
  vector<ll> res(N,INF);
  while(Q.size()){
    NODE q= Q.top();Q.pop();
    if(res[q.pos] == INF){
      res[q.pos] = q.cost;
    }
    else{
      continue;
    }
    for(auto n : g[q.pos]){
      Q.push({n.to,q.cost+n.cost});
    }
  }
  return res;
}
int main(){
  cin.tie(0);
  ios::sync_with_stdio(false);
  int n,m;
  while(cin>>N>>m&&N&&m){
    int a,b,c,d;
    vector<Edge> g[100000],rg[100000];
    rep(i,N){
      cin >> a >> b >> c >> d;
      g[a].push_back({b,c});
      rg[a].push_back({b,d});
      g[b].push_back({a,c});
      rg[b].push_back({a,d});
    }
    int k,p,q,r ;
    cin >> k;
    rep(i,k){
      cin >> p >> q >> r;
      if(r){
        auto ans = dijkstra(rg,p);
        cout << ans[q]<<endl;
      }
      else
      {
        auto ans = dijkstra(g,p);
        cout << ans[q]<<endl;
      }
    }
  }
  return 0;
}

C++: #include <iostream>
#include <algorithm>
#define INF 1000000000
using namespace std;
int mp[2][101][101];
int n,m;
 
int visit(int p,int q,int r) {
 
 
  bool flg[101] = {};
  long long dis[101];
  for(int i=1;i<=m;i++) dis[i] = INF;
 
  dis[p] = 0;
  
  while(1) {
    int mindis = INF;
    int ima;
    for(int i=1;i<=m;i++) 
      if(mindis > dis[i] && flg[i] == 0) {
    mindis = dis[i];
    ima = i;
      }
 
    flg[ima] = 1;
    if(ima == q) return dis[ima];
 
    for(int i=1;i<=m;i++) 
      if(dis[i] > mp[r][ima][i]+dis[ima]) 
    dis[i] = dis[ima] + mp[r][ima][i];
     
  }
 
 
}
 
 
int main (){
 
  while(1) {
    cin >> n >> m;
    if(n == 0 && m == 0) break;
   
  for(int k=0;k<2;k++) 
    for(int i=0;i<=m;i++) 
      for(int j=0;j<=m;j++)
    mp[k][i][j] = INF;
 
     
  for(int i=0;i<n;i++){
  int a , b , cost,time;
  cin >> a >> b >> cost >> time;
  mp[0][a][b] = min(mp[0][a][b] ,cost);
  mp[0][b][a] = min(mp[0][b][a] ,cost);
  mp[1][a][b] = min(mp[1][a][b] ,time);
  mp[1][b][a] = min(mp[1][b][a] ,time);
  }
 
  int qu;
  cin >> qu;
  int p,q,r;
 
  for(int i=0;i<qu;i++) {
    cin >> p >> q >> r;
 
    int ans = visit(p,q,r);
    cout << ans << endl;
  }
  }
   
  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

#define ll long long
#define vvi vector< vector<int> >
#define vi vector<int>
#define All(X) X.begin(),X.end()
#define FOR(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
#define REP(i,n) for(int i=0;i<(int)(n);i++)
#define pb push_back
#define pii pair<int,int>
#define mp make_pair
#define pi 3.14159265359
#define shosu(X) fixed << setprecision(X)
ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
ll lcm(ll a,ll b){return a/gcd(a,b)*b;}
const ll int INF = 1e9;
ll int ti[101][101];//time
ll int co[101][101];//cost
int n,m;
int main(){
	while(1){
		cin >> n >> m; 
		if(n == 0 && m == 0) break;
		REP(i,101) REP(j,101) ti[i][j] = co[i][j] = INF;
		REP(i,101) ti[i][i] = co[i][i] = 0;

		REP(i,n){
			ll int a,b,cost,tim;
			cin >> a >> b >> cost >> tim;
			a--; b--;
			co[a][b] = co[b][a] = cost;
			ti[a][b] = ti[b][a] = tim;
		}
		//Warshall???Floyd Algorithm
		REP(i,m){
			REP(j,m){
				REP(k,m){
					ti[i][j] = min(ti[i][j], ti[i][k] + ti[k][j]);
					co[i][j] = min(co[i][j], co[i][k] + co[k][j]);
				}
			}
		}
		int k;
		cin >> k;
		REP(i,k){
			int a,b,r;
			cin >> a >> b >> r;
			a--; b--;
			if(r == 0) cout << co[a][b] << endl;
			else cout << ti[a][b] << endl;
		}
	}
	return 0;
}