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 <cstdio>
#include <vector>
#include <utility>
#include <queue>
#include <functional>
#define N 101
#define INF 2000000000
using namespace std;

int dist[N];
typedef pair<int,int> pii;

std::vector<pii> e1[N];
std::vector<pii> e2[N];

int dfs(int now,int c){
	if(dist[now]>=c)dist[now]=c;
	else return 0;
	for(int i=0;i<e1[now].size();i++){
		dfs(e1[now][i].second,c+e1[now][i].first);
	}
	return 0;
}

int dijk1(int a,int b){
	dist[a]=0;
	std::priority_queue<pii> pq;
	for(int i=0;i<e2[a].size();i++){
		pq.push(e2[a][i]);
	}
	while(!pq.empty()){
		pii temp=pq.top();
		int now=temp.second;
		int c=temp.first;
		pq.pop();
		if(dist[now]!=INF)continue;
		dist[now]=c;
		for(int i=0;i<e2[now].size();i++){
			pq.push(make_pair(c+e2[now][i].first,e2[now][i].second));
		}
	}
	return -dist[b];
}

int dijk(int a,int b){
	dist[a]=0;
	std::priority_queue<pii> pq;
	for(int i=0;i<e1[a].size();i++){
		pq.push(e1[a][i]);
	}
	while(!pq.empty()){
		pii temp=pq.top();
		int now=temp.second;
		int c=temp.first;
		pq.pop();
		if(dist[now]!=INF)continue;
		dist[now]=c;
		for(int i=0;i<e1[now].size();i++){
			pq.push(make_pair(c+e1[now][i].first,e1[now][i].second));
		}
	}
	return -dist[b];
}

int main(void){
	int a,b,c,d;
	int n,m;
	while(cin>>n>>m,n||m){
		for(int i=0;i<n;i++){
			cin>>a>>b>>c>>d;
			e1[a].push_back(make_pair(-c,b));
			e2[a].push_back(make_pair(-d,b));
		}
		int k;
		cin>>k;
		while(k--){
			for(int i=1;i<=m;i++)dist[i]=INF;
			cin>>a>>b>>c;
			if(c) cout<<dijk1(a,b)<<endl;
			else cout<<dijk(a,b)<<endl;
			// for(int i=1;i<=m;i++)printf("dist[%d]:%d\n",i,dist[i]);
		}
	}
	return 0;
}

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

using namespace std;

typedef vector< int > VI;
typedef vector< VI > VVI;
typedef vector< VVI > VVVI;

const int INF = INT_MAX / 2;

int main()
{
	cin.tie( 0 );
	ios::sync_with_stdio( false );

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

		if ( !( n | m ) )
		{
			break;
		}

		VVVI G( m, VVI( m, VI( 2, INF ) ) );

		for ( int i = 0; i < m; i++ )
		{
			G[i][i][0] = G[i][i][1] = 0;
		}

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

			a--;
			b--;

			G[a][b][0] = G[b][a][0] = cost;
			G[a][b][1] = G[b][a][1] = time;
		}

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

		int k;
		cin >> k;

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

			p--;
			q--;

			cout << G[p][q][r] << endl;
		}
	}

	return 0;
}

C++: #include <iostream>
#include <algorithm>
#define INF 1000000
using namespace std;
int cost[100][100];
int time[100][100];
int d[100];
int m;

void dcost(int s) {
	bool used[100];
	fill(used, used + 100, false);
	fill(d, d + 100, INF);
	d[s] = 0;
	while (1) {
		int v = -1;
		for (int u = 0; u < m; ++u) {
			if (!used[u] && (v == -1 || d[u] < d[v])) v = u;
		}
		if (v == -1) break;
		used[v] = true;

		for (int u = 0; u < m; ++u) {
			d[u] = d[u] < d[v] + cost[v][u] ? d[u] : d[v] + cost[v][u];
		}
	}
}

void dtime(int s) {
	bool used[100];
	fill(used, used + 100, false);
	fill(d, d + 100, INF);
	d[s] = 0;
	while (1) {
		int v = -1;
		for (int u = 0; u < m; ++u) {
			if (!used[u] && (v == -1 || d[u] < d[v])) v = u;
		}
		if (v == -1) break;
		used[v] = true;

		for (int u = 0; u < m; ++u) {
			d[u] = d[u] < d[v] + time[v][u] ? d[u] : d[v] + time[v][u];
		}
	}
}

int main() {
	int n, k, a, b, p, q, r;
	
	while (cin >> n >> m, !(n == 0 && m == 0)) {
		fill(cost[0], cost[100], INF);
		fill(time[0], time[100], INF);
		while (n--) {
			cin >> a >> b;
			a--; b--;
			cin >> cost[a][b] >> time[a][b];
			cost[b][a] = cost[a][b];
			time[b][a] = time[a][b];
		}
		cin >> k;
		while (k--) {
			cin >> p >> q >> r;
			p--; q--;
			if (r == 1) dtime(p);
			else dcost(p);
			cout << d[q] << endl;
		}
		
	}
	return 0;
}