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<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(1){
    cin>> n>> m;
    if(n==0 && m==0) break;
  
  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;
    }
  }

  }
}

C++: #include <bits/stdc++.h>
#define r(i,n) for(int i=0;i<n;i++)
#define INF 1<<29
using namespace std;
main(){
  int m,n;
  while(cin>>m>>n,n){
    int a1[n][n],a2[n][n],q,w,e,r;
    r(i,n)r(j,n){
      if(i==j)a2[i][j]=a1[i][j]=0;
      else a2[i][j]=a1[i][j]=INF;
    }
    while(m--){
      scanf("%d%d%d%d",&q,&w,&e,&r)q--;w--;
      a1[q][w]=e;
      a2[q][w]=r;
    }
    r(k,n)r(i,n)r(j,n){
      a1[i][j]=min(a1[i][j],a1[i][k]+a1[k][j]);
      a2[i][j]=min(a2[i][j],a2[i][k]+a2[k][j]);
    }
    cin>>e;
    while(e--){
      scanf("%d%d%d",&q,&w,&e);q--;w--;
      if(r)cout<<a2[w][q]<<endl;
      else cout<<a1[w][q]<<endl;
    }
  }
}

C++: #include<cstdio>
#include<cstring>
#include<cstdlib>
#include<algorithm>
#include<functional>
#include<iostream>
#define INF 1000000
using namespace std;
void cWarshall_Floyd();
void tWarshall_Floyd();
int glid_cost[101][101];
int glid_tim[101][101];
int n,m,a,b,tim,cost,qs,p,q,r;
void cWarshall_Floyd()
{
	int i,j,k;
	for(k=0;k<m;k++) {
		for(i=0;i<m;i++) {
			for(j=0;j<m;j++) {
				glid_cost[i][j]=min(glid_cost[i][j],glid_cost[i][k]+glid_cost[k][j]);
			}
		}
	}
}
void tWarshall_Floyd()
{
	int i,j,k;
	for(k=0;k<m;k++) {
		for(i=0;i<m;i++) {
			for(j=0;j<m;j++) {
				glid_tim[i][j]=min(glid_tim[i][j],glid_tim[i][k]+glid_tim[k][j]);
			}
		}
	}
}
int main(void)
{
	ios::sync_with_stdio(false);
	int i,j,k;
	while(1) {
		cin>>n>>m;
		if(n==0&&m==0) break;
		for(i=0;i<m;i++) {
			for(j=0;j<m;j++) {
				glid_cost[i][j]=INF;
				glid_tim[i][j]=INF;
			}
		}
		for(i=0;i<m;i++) {
			glid_cost[i][i]=0;
			glid_tim[i][j]=0;
		}
		for(i=0;i<n;i++) {
			cin>>a>>b>>cost>>tim;
			a--;b--;
			glid_cost[a][b]=cost;
			glid_cost[b][a]=cost;
			glid_tim[a][b]=tim;
			glid_tim[b][a]=tim;
		}
		cin>>qs;
		for(i=0;i<qs;i++) {
			cin>>p>>q>>r;
			if(r==0) {
				cWarshall_Floyd();
				cout<<glid_cost[p-1][q-1]<<endl;
			}
			else {
				tWarshall_Floyd();
				cout<<glid_tim[p-1][q-1]<<endl;
			}
		}
	}
	return 0;
}

C++: #include <bits/stdc++.h>

const int MOD = 1e9 + 7;
const int iINF = 1000000000;
const long long int llINF = 1000000000000000000;
const double PI = acos(-1.0);
#define rep(i, n) for (int i = 0; i < (n); i++)

using namespace std;
using ll = long long int;
using P = pair<int, int>;
using edge = struct
{
    int to;
    int cost;
};

int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};

int costs[100][100];
int times[100][100];

void Warshall_Floyd(int N, int (&cost)[100][100])
{
    rep(k, N) rep(i, N) rep(j, N)
        cost[i][j] = min(cost[i][j], cost[i][k] + cost[k][j]);
}

int main()
{
    int N, M;
    while (cin >> M >> N && N)
    {
        rep(i, 100) rep(j, 100) costs[i][j] = iINF;
        rep(i, 100) rep(j, 100) times[i][j] = iINF;

        rep(i, M)
        {
            int a, b, c, t;
            cin >> a >> b >> c >> t;
            a--;
            b--;

            costs[a][b] = min(costs[a][b], c);
            costs[b][a] = min(costs[b][a], c);

            times[a][b] = min(times[a][b], t);
            times[b][a] = min(times[b][a], t);
        }

        Warshall_Floyd(N, costs);
        Warshall_Floyd(N, times);

        int K;
        cin >> K;

        int p, q, r;

        rep(i, K)
        {
            cin >> p >> q >> r;
            p--;
            q--;

            cout << (r == 1 ? times[p][q] : costs[p][q]) << endl;
        }
    }

    return 0;
}