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);
}
ll N;
vector<vector<ll>> warshall_floyd(vector<vector<ll>> d){
  rep(k,N){
    rep(i,N){
      rep(j,N){
        d[i][j] = min(d[i][j],d[i][k] + d[k][j]);
      }
    }
  }
  return d;
}
int main(){
  cin.tie(0);
  ios::sync_with_stdio(false);
  ll m;
  while(cin>>N>>m&&N&&m){
    int a,b,c,d;
    vector<vector<ll>> time(N+1,vector<ll>(N+1,inf));
    vector<vector<ll>> cost(N+1,vector<ll>(N+1,inf));
    rep(i,N){
      cin >> a >> b >> c >> d;
      time[a][b] = d;
      cost[a][b] = c;
      time[b][a] = d;
      cost[b][a] = c;
    }
    int k,p,q,r ;
    auto T = warshall_floyd(time);
    auto C = warshall_floyd(cost);
    cin >> k;
    rep(i,k){
      cin >> p >> q >> r;
      if(r){
        cout << T[p][q]<<endl;
      }
      else{
        cout << C[p][q]<<endl;
      }
    }
  }
  return 0;
}

C++: #include <cstdio>
#include <vector>
#include <queue>
#include <functional>

using namespace std;

#define fst first
#define scd second
#define PB push_back
#define MP make_pair
#define rep(i,x) for(int i=0;i<(x);++i)

typedef pair<int, int> pii;

const int inf = 1e9;

struct edge {
	int to, cost, time;
	edge(int to0,int cost0,int time0) {
		to = to0; cost = cost0; time = time0;
	};
};

vector<edge> G[100];
int d[100];

int N, M;

void dijkstra(int s, int mode)
{
	priority_queue<pii, vector<pii>, greater<pii> > q;

	fill(d, d + M, inf);
	d[s] = 0;

	q.push(MP(0, s));

	while (q.size()) {
		pii p = q.top(); q.pop();
		int v = p.scd;
		if (d[v] < p.fst) continue;
		rep(u, G[v].size()) {
			edge e = G[v][u];
			int a = mode == 0 ? e.cost : e.time;
			if (d[e.to] > d[v] + a) {
				d[e.to] = d[v] + a;
				q.push(MP(d[e.to], e.to));
			}
		}
	}
}

signed main()
{
	while (scanf("%d %d", &N, &M), N || M) {
		rep(i, M) G[i].clear();

		rep(i, N) {
			int a, b, cost, time; scanf("%d %d %d %d", &a, &b, &cost, &time); a--; b--;
			G[a].PB(edge(b, cost, time));
			G[b].PB(edge(a, cost, time));
		}

		int K; scanf("%d", &K);

		rep(i, K) {
			int p, q, r; scanf("%d %d %d", &p, &q, &r); p--; q--;
			dijkstra(p, r);
			printf("%d\n", d[q]);
		}
	}
}

C++: #include<iostream>
#include<set>
#define loop(i,a,b) for(int i=a;i<b;i++)
#define rep(i,a) loop(i,0,a)
#define INF 1e8
using namespace std;
int n,m,k,a,b,c,alt,p,q,r;
long long cost[101][101],tm[101][101],d[101];
bool used[101];

void dfunc(int s,int r){
	rep(i,101){
		used[i]=true;
		d[i]=INF;
	}
	d[s]=0;
	while(1){
		int mem=INF,now=-1;
		rep(i,101){
			if(used[i] && mem>d[i]){
				now=i;
				mem=d[i];
			}
		}
		if(now==-1)break;
		used[now]=false;
		rep(i,101){
			if(r==0){
				if(cost[now][i]!=INF)d[i]=min(d[i],d[now]+cost[now][i]);
			}else{
				if(tm[now][i]!=INF)d[i]=min(d[i],d[now]+tm[now][i]);
			}
		}
	}
}

int main(){
	while(cin>>n>>m,n||m){
		rep(i,101)rep(j,101){
			cost[i][j]=INF;
			tm[i][j]=INF;
		}
		rep(i,n){
			cin>>a>>b>>c>>alt;
			a--;
			b--;
			cost[b][a]=cost[a][b]=c;
			tm[b][a]=tm[a][b]=alt;
		}
		cin>>k;
		rep(i,k){
			cin>>p>>q>>r;
			dfunc(p-1,r);
			cout<<d[q-1]<<endl;
		}
	}
	return 0;
}