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 <iostream>
#include <vector>
#include <queue>
#define FOR(i,a,b) for(int i=(a); i<(b); i++)
#define pb push_back
using namespace std;

const int INF=10000000;
int V;
struct edge {
    int to,money,time;
};
struct state {
    int from, d;
    bool operator<(const state& a)const{
        return d>a.d;
    }
};
vector<vector<edge> > G;

int d[111];
int ds(int s,int g, int r){
    FOR(i,0,111)d[i]=INF;
    d[s]=0;
    priority_queue<state> q;
    q.push({s,0});
    while(q.size()){
        state sta=q.top();
        q.pop();
        int from=sta.from;
        if(d[from]<sta.d) continue;
        FOR(i,0,G[from].size()){
            const edge& e=G[from][i];
            int to=e.to;
            int cost=r?e.time:e.money;
            if(d[to]>d[from]+cost){
                d[to]=d[from]+cost;
                q.push({to,d[to]});
            }
        }
    }
    return d[g];
}

int main(){
    int n;
    while(1){
        cin>>n>>V;
        if(!(n||V)) break;
        G=vector<vector<edge> >(n+1);
        FOR(i,0,n){
            int a,b,m,t;cin>>a>>b>>m>>t;
            G[a].pb({b,m,t});
            G[b].pb({a,m,t});
        }
        int k;cin>>k;
        FOR(i,0,k){
            int p,q,r;cin>>p>>q>>r;
            cout<<ds(p,q,r)<<endl;
        }
    }
}

C++: #include <iostream>
#include <queue>
#include <utility>
#include <vector>
#include <functional>

struct Node {
	std::vector<int> edgesDest;
	std::vector<int> edgesCost[2];

	bool done = false;
	int cost = -1;

	bool operator < (const Node& n) {
		return cost < n.cost;
	}
};

int main() {
	int n, m;
	std::vector<Node> nodes;
	using Pair = std::pair<int, int>;

	while (std::cin >> n >> m) {
		if (n == 0 && m == 0)
			break;

		nodes.clear();
		nodes.resize(m);
		for (int i = 0; i < n; ++i) {
			int a, b, c, t;
			std::cin >> a >> b >> c >> t;

			nodes[a - 1].edgesDest.push_back(b - 1);
			nodes[a - 1].edgesCost[0].push_back(c);
			nodes[a - 1].edgesCost[1].push_back(t);

			nodes[b - 1].edgesDest.push_back(a - 1);
			nodes[b - 1].edgesCost[0].push_back(c);
			nodes[b - 1].edgesCost[1].push_back(t);
		}

		int k;
		std::cin >> k;
		for (int i = 0; i < k; ++i) {
			for (int j = 0; j < nodes.size(); ++j)
				nodes[j].done = false, nodes[j].cost = -1;

			int p, q, r;
			std::cin >> p >> q >> r;
			--p, --q;

			nodes[p].cost = 0;

			std::priority_queue<Pair, std::vector<Pair>, std::greater<Pair>> queue;
			queue.push(Pair(0, p));
			while (!queue.empty()) {
				const Pair& qtop = queue.top();
				Node& node = nodes[qtop.second];

				if (node.done) {
					queue.pop();
					continue;
				}
				if (qtop.second == q) {
					std::cout << node.cost << std::endl;
					break;
				}
				queue.pop();

				node.done = true;
				for (int j = 0; j < node.edgesDest.size(); ++j) {
					int dest = node.edgesDest[j];
					int cost = node.cost + node.edgesCost[r][j];

					if (nodes[dest].cost < 0 || cost < nodes[dest].cost) {
						nodes[dest].cost = cost;
						queue.push(Pair(cost, dest));
					}
				}
			}
		}
	}

	return 0;
}

C++: #include <iostream>
#include <algorithm>
using namespace std;
int main(){
  int road1[111][111];
  int road2[111][111];
  int n,m;
  int a,b,cost,time;
  int p,q,r;
  int x;
  while(1){
    for(int i=0;i<111;i++){
      for(int j=0;j<111;j++){
    road1[i][j]=road2[i][j]=111111111;
      }
    }
    cin >> n >> m;
    if(n==0 && m==0)break;
    for(int i=0;i<n;i++){
      cin >> a >> b >> cost >> time;
      road1[a][b]=road1[b][a]=cost;
      road2[a][b]=road2[b][a]=time;
    }
 
    for(int k=1;k<=m;k++){
      for(int i=1;i<=m;i++){
    for(int j=1;j<=m;j++){
      if(road1[i][j]>road1[i][k]+road1[k][j]){
        road1[i][j]=road1[i][k]+road1[k][j];
      }
      if(road2[i][j]>road2[i][k]+road2[k][j]){
        road2[i][j]=road2[i][k]+road2[k][j];
      }
    }
      }
    }
     
    cin >> x;
    for(int i=0;i<x;i++){
      cin >> p >> q >> r;
      cout << (r==0 ? road1[p][q] : road2[p][q]) << endl;
    }
  }
}