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>
using namespace std;

const int INF = 1000000000;

int main()
{
	while(true){
		int n, m;
		cin >> n >> m;

		if(n==0 && m==0)
			break;

		int C[100][100];
		int T[100][100];
		for(int i=0; i<m; i++){
			for(int j=0; j<m; j++){
				if(i==j){
					C[i][j] = T[i][j] = 0;
				}
				else{
					C[i][j] = T[i][j] = INF;
				}
			}
		}

		for(int i=0; i<n; i++){
			int a, b, c, t;
			cin >> a >> b >> c >> t;

			C[a-1][b-1] = C[b-1][a-1] = c;
			T[a-1][b-1] = T[b-1][a-1] = t;
		}

		int N,p,q,r;
		int dt[100][100];
		int dc[100][100];
		for(int i=0;i<m;i++){
			for(int j=0;j<m;j++){
				dt[i][j]=T[i][j];
			}
		}
		for(int k=0;k<m;k++){
			for(int i=0;i<m;i++){
				for(int j=0;j<m;j++){
					if(dt[i][j]>dt[i][k]+dt[k][j]){
						dt[i][j]=dt[i][k]+dt[k][j];
					}
				}
			}
		} 
		for(int i=0;i<m;i++){
			for(int j=0;j<m;j++){
				dc[i][j]=C[i][j];
			}
		}
		for(int k=0;k<m;k++){
			for(int i=0;i<m;i++){
				for(int j=0;j<m;j++){
					if(dc[i][j]>dc[i][k]+dc[k][j]){
						dc[i][j]=dc[i][k]+dc[k][j];
					}
				}
			}
		} 
		cin >> N;
		for(int I=0;I<N;I++){
			cin >> p >> q >> r;
			cout << (r?dt[p-1][q-1]:dc[p-1][q-1]) << endl;
		}
		
		/*int k,p,q,r;
		cin >> k;
		for(int I=0;I<k;I++){
			int d[m];
			bool u[m];
			cin >> p >> q >> r;
			for(int i=0;i<m;i++){
				d[i] = INF;
				u[i] = false;
			}
			d[p-1]=0;

			while(1){
				int v = -1;
				for(int i=0;i<m;i++){
					if(u[i])continue;
					if(v==-1||d[i]<d[v]){
						v = i;
					}
				}
				if(v==-1)break;
				u[v]=true;

				for(int i=0;i<m;i++){
					if(r){
						if(d[i]>d[v]+T[v][i]){
							d[i]=d[v]+T[v][i];
						}
					}else{
						if(d[i]>d[v]+C[v][i]){
							d[i]=d[v]+C[v][i];
						}
					}
				}
			}
		
			cout << d[q-1] << endl;
		}*/		
	}

	return 0;
}

C++: #include <iostream>
#include <vector>
#include <queue>
#include <algorithm>
#include <functional>
#define inf 4000000
using namespace std;

int main(){
    int n, m, k;
    while(cin >> n >> m){
        if(n == 0 && m == 0) break;
        vector<vector<int>> cost(m+1,vector<int>(m+1,inf));
        vector<vector<int>> tim(m+1,vector<int>(m+1,inf));
        for(int i = 0;i<n;i++){
            int a, b;
            cin >> a >> b;
            cin >> cost[a][b] >> tim[a][b];
            cost[b][a] = cost[a][b];
            tim[b][a] = tim[a][b];
        }
        cin >> k;
        for(int i = 0;i<k;i++){
            vector<long long int> dkt(m+1,inf);
            vector<bool> checked(m+1,false);
            // priority_queue<pair<int,int>,greater<int>> pque;
            int p, q, r;
            cin >> p >> q >> r;
            dkt[p] = 0;
            // pque.push(pair<int,int>(0,p));
            while(!checked[q]){
                int top = inf, min = inf;
                for(int j = 1;j<m+1;j++){
                    if(!checked[j] && min > dkt[j]){
                        top = j;
                        min = dkt[j];
                        checked[j] = true;
                        break;
                    }
                }
                for(int j = 1;j<m+1;j++){
                    if(checked[j] || top == j) continue;
                    if(r == 0){
                        dkt[j] = std::min(dkt[j],(dkt[top]+cost[top][j]));
                    }
                    else{
                        dkt[j] = std::min(dkt[j],dkt[top]+tim[top][j]);
                    }
                }
            }
            cout << dkt[q] << endl;
        }
    }
    return 0;
}

C++: #include<iostream>
#define loop(i,a,b) for(int i=a;i<b;i++)
#define rep(i,a) loop(i,0,a)
#define INF 1e9
using namespace std;
typedef long long ll;

ll min(ll a,ll b){
	if(a>b)return b;
	else return a;
}


int main(){
	int n,m,a,b,cost,time,l,p,q,r;
	while(cin>>n>>m,n||m){
		ll mt[m][m],mc[m][m];
		rep(i,m)rep(j,m)mt[i][j]=mc[i][j]=INF;
		rep(i,n){
			cin>>a>>b>>cost>>time;
			mt[a-1][b-1]=mt[b-1][a-1]=time;
			mc[a-1][b-1]=mc[b-1][a-1]=cost;
		}
		rep(k,m){
			rep(i,m){
				rep(j,m){
					mt[i][j]=min(mt[i][j],mt[i][k]+mt[k][j]);
					mc[i][j]=min(mc[i][j],mc[i][k]+mc[k][j]);
				}
			}
		}
		cin>>l;
		rep(i,l){
			cin>>p>>q>>r;
			if(r==0)cout<<mc[p-1][q-1]<<endl;
			else cout<<mt[p-1][q-1]<<endl;
		}
	}
	return 0;
}

C++: #include<iostream>
#include<algorithm>
using namespace std;

const int MAX=1000;
const int INF=(1<<21);

int main(){

  int n,m;
  int a,b,cost,time;
  int p,q,r;
  int rail_cost[MAX][MAX];
  int rail_time[MAX][MAX];

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

  for(int i=0;i<m;i++){
    for(int j=0;j<m;j++){
      rail_cost[i][j]=INF;
      rail_time[i][j]=INF;
    }
  }

  for(int i=0;i<n;i++){
    cin>> a>> b>> cost>> time; 
    rail_cost[a-1][b-1]=cost;
    rail_time[a-1][b-1]=time;
  }

  for(int i=0;i<m;i++){
    for(int j=0;j<m;j++){
      for(int k=0;k<m;k++){
	rail_cost[j][k]=min(rail_cost[j][k],rail_cost[j][i]+rail_cost[i][k]);
	rail_time[j][k]=min(rail_time[j][k],rail_time[j][i]+rail_time[i][k]);
      }
    }
  }

  cin>> n;
  for(int i=0;i<n;i++){
    cin>> p>> q>> r;
    if(r==0){
      cout<< rail_cost[p-1][q-1]<< endl;
    }else{
      cout<< rail_time[p-1][q-1]<< endl;
    }
  }

  }
}