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<bits/stdc++.h>
#define LL long long int
#define INF 210000000
using namespace std;
int main(void)
{
	int i,j,k,n,m,cost,time,a,b,wrc[100][100],wrt[100][100];
	while(1) {
		cin>>n>>m;
		if(n==0&&m==0) break;
		for(i=0;i<m;i++)for(j=0;j<m;j++) wrc[i][j]=INF,wrt[i][j]=INF;
		for(i=0;i<m;i++) wrc[i][i]=0,wrt[i][i]=0;
		for(i=0;i<n;i++) {
			cin>>a>>b>>cost>>time;
			a--,b--;
			wrc[a][b]=cost,wrc[b][a]=cost;
			wrt[a][b]=time,wrt[b][a]=time;
		}
		for(k=0;k<m;k++)for(i=0;i<m;i++)for(j=0;j<m;j++) {
			wrc[i][j]=min(wrc[i][j],wrc[i][k]+wrc[k][j]);
			wrt[i][j]=min(wrt[i][j],wrt[i][k]+wrt[k][j]);
		}
		int p,r,c,cc;
		cin>>cc;
		for(i=0;i<cc;i++) {
			cin>>p>>r>>c;
			p--,r--;
			if(c==0) cout<<wrc[p][r]<<endl;
			else cout<<wrt[p][r]<<endl;
		}
	}
}

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

#define INF 1e9+7

int main(){
	int n,m;
	while(1){
		cin>>n>>m;
		if(n==0&&m==0)break;
		vector<vector<int> > cost(m,vector<int>(m,INF));
		vector<vector<int> > timea(m,vector<int>(m,INF));
		
		for(int i=0;i<n;i++){
			int a,b;
			cin>>a>>b;
			a--;
			b--;
			cin>>cost[a][b]>>timea[a][b];
			cost[b][a]=cost[a][b];
			timea[b][a]=timea[a][b];
		}
		
		for(int i=0;i<m;i++){
			cost[i][i]=0;
			timea[i][i]=0;
		}
		
		for(int k=0;k<m;k++){
			for(int i=0;i<m;i++){
				for(int j=0;j<m;j++){
					cost[i][j]=min(cost[i][j],cost[i][k]+cost[k][j]);
					timea[i][j]=min(timea[i][j],timea[i][k]+timea[k][j]);
				}
			}
		}
		
		int k;
		cin>>k;
		for(int i=0;i<k;i++){
			int p,q,r;
			cin>>p>>q>>r;
			p--;
			q--;
			if(r==0)cout<<cost[p][q]<<endl;
			if(r==1)cout<<timea[p][q]<<endl;
		}
	}
	return 0;
}

C++: #include<iostream>
#include<algorithm>
const int INF = 1<<20;
const int N = 101;
int cost[N][N];
int tim[N][N];
using namespace std;
int main()
{
	int n, m, a, b, co, ti,r;
	while (1){
		cin >> n >> m;
		if (n == 0 && m == 0)return 0;
		for (int i = 0; i < m+2; i++){
			for (int i2 = 0; i2 < m+2; i2++){
				cost[i][i2] = INF;
				tim[i][i2] = INF;
			}
		}
		for (int i = 0; i < n; i++){
			cin >> a >> b >> co >> ti;
			cost[a][b] = co;
			cost[b][a] = co;
			tim[a][b] = ti;
			tim[b][a] = ti;
		}
		for (int k = 0; k < m+1; ++k)
			for (int i = 0; i < m+1; ++i)
				for (int j = 0; j < m+1; ++j)
				{
					cost[i][j] = min(cost[i][j], cost[i][k] + cost[k][j]);
					tim[i][j] = min(tim[i][j], tim[i][k] + tim[k][j]);
				}
		cin >> m;
		for (int i = 0; i < m; i++){
			cin >> a >> b >> r;
			if (r == 0){
				cout << cost[a][b] << endl;
			}
			else
				cout << tim[a][b] << endl;
		}
	}
}