Go: // Warshall–Floyd Algorithm

package main

import (
	"bufio"
	"os"
	"strings"
	"strconv"
	"fmt"
)

var scanner = bufio.NewScanner(os.Stdin)

const INF = 0x7FFFFFFF

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
				} else {
					c_dist[i][j] = c_matrix[i][j]
				}
				if c_matrix[i][j] == 0{
					c_prev[i][j] = -1
				} else {
					c_prev[i][j] = i
				}
				if t_matrix[i][j] == 0{
					t_dist[i][j] = INF
				} else {
					t_dist[i][j] = t_matrix[i][j]
				}
				if t_matrix[i][j] == 0{
					t_prev[i][j] = -1
				} else {
					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 <iomanip>
#include <sstream>
#include <stdio.h>
#include <vector>
#include <stack>
#include <queue>
#include <algorithm>
#include <math.h>
#include <utility>
#include <string>
#include <ctype.h>
#include <cstring>
#include <cstdio>
#include <sstream>
#include <functional>

using namespace std;

#define FOR(i,k,n) for(int i = (k); i < (n); i++)
#define REP(i,n) FOR(i,0,n)
#define INF 999999999
#define ll long long
//#define scanf scanf_s


int main()
{

	int cost[101][101];
	int time_[101][101];

	while (1)
	{
		int n, m;
		cin >> n >> m; if (n == 0 && m == 0) break;
		REP(i, 101)REP(j, 101)
		{
			if (i == j)
			{
				cost[i][j] = 0;
				time_[i][j] = 0;
			}
			else
			{
				cost[i][j] = INF;
				time_[i][j] = INF;
			}
		}

		REP(i, n)
		{
			int a, b, c, t;
			cin >> a >> b >> c >> t;
			a--; b--;
			cost[a][b] = cost[b][a] = c;
			time_[a][b] = time_[b][a] = t;
		}

		REP(i, m)REP(j, m)REP(k, m)
		{
			cost[i][j] = min(cost[i][j], cost[i][k] + cost[k][j]);
			time_[i][j] = min(time_[i][j], time_[i][k] + time_[k][j]);
		}
		int k;
		cin >> k;
		REP(i, k)
		{
			int p, q, r;
			cin >> p >> q >> r;
			p--; q--;
			if (r == 0) cout << cost[p][q] << endl;
			else cout << time_[p][q] << endl;
		}
	}
	return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#include<queue>

using namespace std;

const int INF=1e9;

//struct edge{int to,cost,time;};
struct edge{int cost,time;};

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

	//vector<edge> es[n];
	edge es[m][m];
	for(int i=0;i<m;i++)for(int j=0;j<m;j++) es[i][j] = (edge){INF,INF};

	int a,b,cost,time;
	for(int i=0;i<n;i++){
		cin >> a >> b >> cost >> time;
	//	es[a].emplace_back((edge){b,cost,time});
		es[a-1][b-1] = (edge){cost,time};
		es[b-1][a-1] = es[a-1][b-1];
	}

	int d_cost[m][m];
	int d_time[m][m];
	for(int i=0;i<m;i++){
		for(int j=0;j<m;j++){
			d_cost[i][j] = es[i][j].cost;
			d_time[i][j] = es[i][j].time;
		}
	}

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

	int k;
	cin >> k;
	for(int n=0;n<k;n++){
		int p,q,r;
		cin >> p >> q >> r;

		if(r==0) cout << d_cost[p-1][q-1] << "\n";
		else	cout << d_time[p-1][q-1] << "\n";
	}
	cin >> k >> k;

	return 0;
}

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

using namespace std;

int main(void) {
	int n,m,k,p,q,r;
	while (cin >> n >> m && n && m) {
		int dp[101][101][2];
		for (int i = 0; i < m + 1; ++i) {
			for (int j = 0; j < m + 1; ++j) {
				for (int k = 0; k < 2; ++k) {
					if (i == j) {
						dp[i][j][k] = 0;
					}
					else {
						dp[i][j][k] = 1001;
					}
				}
			}
		}

		int a,b,c,t;
		for (int i = 0; i < n; ++i) {
			cin >> a >> b >> dp[a][b][0] >> dp[a][b][1];
			dp[b][a][0] = dp[a][b][0];
			dp[b][a][1] = dp[a][b][1];
		}

		for (int mode = 0; mode < 2; ++mode) {
			for (int k = 1; k < m + 1; ++k) {
				for (int i = 1; i < m + 1; ++i) {
					for (int j = 1; j < m + 1; ++j) {
						dp[i][j][mode] = min(dp[i][j][mode], dp[i][k][mode]+dp[k][j][mode]);
					}
				}
			}
		}

		cin >> k;
		for (int i = 0; i < k; ++i) {
			cin >> p >> q >> r;
			cout << dp[p][q][r] << endl;
		}
	}
	return 0;
}