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>
#include<vector>
#include<queue>
#include<map>
#define pb push_back
#define INF 1000000000

using namespace std;
typedef pair<int,int> P;
int n;

struct edge{
	int to,cost;
	edge(int to,int cost):to(to),cost(cost){}
};
vector<vector<edge> > G1,G2;


int dijkstra1(int s,int t){
	priority_queue<P,vector<P> , greater<P> > que;
	vector<int> d(n,INF);
	d[s]=0;
	que.push(P(0,s));
	while(!que.empty()){
		P q=que.top();
		que.pop();
		int now=q.second,dist=q.first;
		if(now==t){
			return dist;
		}
		
		if(d[now]<dist)
			continue;
		
		for(int i=0;i<(int)G1[now].size();i++){
			if(G1[now][i].cost+dist<d[G1[now][i].to]){
				que.push(P(G1[now][i].cost+dist,G1[now][i].to));
				d[G1[now][i].to]=G1[now][i].cost+dist;
			}
		}
	}
	return -1;
	
}
int dijkstra2(int s,int t){
	priority_queue<P,vector<P> , greater<P> > que;
	vector<int> d(n,INF);
	d[s]=0;
	que.push(P(0,s));
	while(!que.empty()){
		P q=que.top();
		que.pop();
		int now=q.second,dist=q.first;
		if(now==t){
			return dist;
		}
		
		if(d[now]<dist)
			continue;
		
		for(int i=0;i<(int)G2[now].size();i++){
			if(G2[now][i].cost+dist<d[G2[now][i].to]){
				que.push(P(G2[now][i].cost+dist,G2[now][i].to));
				d[G2[now][i].to]=G2[now][i].cost+dist;
			}
		}
	}
	return -1;
}
int main(){
	int m;
	while(cin>>m>>n,n||m){
		
		G1.resize(n);
		G2.resize(n);
		cout<<m<<endl;
		for(int i=0;i<m;i++){
			int a,b,c,t;
			cin>>a>>b>>c>>t;a--;b--;
			G1[a].pb(edge(b,c));
			G1[b].pb(edge(a,c));
			G2[a].pb(edge(b,t));
			G2[b].pb(edge(a,t));
		}

		
		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<<dijkstra1(p,q)<<endl;
			}else
				cout<<dijkstra2(p,q)<<endl;
			
			
		}
		
	}
	
	return 0;
}

C++: class _in{struct my_iterator{int it;const bool rev;explicit constexpr my_iterator(int it_, bool rev=false):it(it_),rev(rev){}constexpr int operator*(){return it;}constexpr bool operator!=(my_iterator& r){return it!=r.it;}void operator++(){rev?--it:++it;}};const my_iterator i,n;public:explicit constexpr _in(int n):i(0),n(n){}explicit constexpr _in(int i,int n):i(i,n<i),n(n){}constexpr const my_iterator& begin(){return i;}constexpr const my_iterator& end(){return n;}};

#include <bits/stdc++.h>
using namespace std;

const int INF = 1e9;
int dist[100][100];
int cost[100][100];
inline void chmin(int& a, int b) { a = min(a, b); }
int main() {
    cin.tie(0); ios::sync_with_stdio(false);
    for(int N, M; cin >> N >> M && N; ) {
        for(int i : _in(100)) {
            fill_n(dist[i], 100, INF);
            fill_n(cost[i], 100, INF);
            dist[i][i] = cost[i][i] = 0;
        }
        for(int _ : _in(N)) {
            int a, b, co, di;
            cin >> a >> b >> co >> di;
            --a;
            --b;
            chmin(dist[a][b], di);
            chmin(dist[b][a], di);
            chmin(cost[a][b], co);
            chmin(cost[b][a], co);
        }
        for(int k : _in(M)) for(int i : _in(M)) for(int j : _in(M)) {
            chmin(dist[i][j], dist[i][k] + dist[k][j]);
            chmin(cost[i][j], cost[i][k] + cost[k][j]);
        }
        int K; cin >> K;
        while(K--) {
            int p, q, r;
            cin >> p >> q >> r;
            --p;
            --q;
            cout << (r == 0 ? cost[p][q] : dist[p][q]) << '\n';
        }
    }
    return 0;
}

C++: #include <cstdio>
#include <algorithm>
using namespace std;
int cost[100][100],Time[100][100];
int n,m;
void Min(int cost[100][100]) {
	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]);
			}
		}
	}
}
int main() {
	while(scanf("%d %d",&n,&m),n) {
		for(int i=0;i<m;i++) {
			for(int j=0;j<m;j++)  {
				if(i!=j)cost[i][j]=Time[i][j]=1<<27;
				else cost[i][j]=Time[i][j]=0;
			}
		}
		int a,b;
		for(int i=0;i<n;i++) {
			scanf("%d %d",&a,&b);
			scanf("%d %d",&cost[a-1][b-1],&Time[a-1][b-1]);
			cost[b-1][a-1]=cost[a-1][b-1];
			Time[b-1][a-1]=Time[b-1][a-1];
		}
		Min(cost);Min(Time);
		int k,p,q,r;
		scanf("%d",&k);
		for(int i=0;i<k;i++) {
			scanf("%d %d %d",&p,&q,&r);
			if(r)printf("%d\n",Time[p-1][q-1]);
			else printf("%d\n",cost[p-1][q-1]);
		}
	}
}

C++: #include <vector>
#include <map>
#include <stack>
#include <queue>
#include <cstring>
#include <string>
#include <sstream>
#include <algorithm>
#include <iomanip>
#include <iostream>

#define VARIABLE(x) cerr << #x << "=" << x << endl
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define REP(i,m,n) for (int i=m;i<(int)(n);i++)

const int INF = 10000000;
using namespace std;
typedef long long  ll;
const int MAX = 10000;

/** Problem0200 : Traveling Alone : One-way Ticket of Youth **/
int costG[100][100];
int timeG[100][100];

int main()
{
	int n, m, a, b, c, t;
	
	while (cin >> n >> m, n!=0 && m!=0) {
		rep(i, 100) {
			rep(j, 100) {
				costG[i][j]=INF;
				timeG[i][j]=INF;
			}
		}
		
		rep(k, n) {
			cin >> a >> b >> c >> t;
			a--; b--;
			costG[a][b] = c;
			costG[b][a] = c;
			timeG[a][b] = t;
			timeG[b][a] = t;
		}
		
		rep(k, m) {
			rep(i, m) {
				rep(j, m) {
					costG[i][j] = min(costG[i][j], costG[i][k]+costG[k][j]);
					timeG[i][j] = min(timeG[i][j], timeG[i][k]+timeG[k][j]);
				}
			}
		}
		
		int k, p, q, r;
		cin >> k;
		rep(i, k) {
			cin >> p >> q >> r;
			p--; q--;
			if (r==0) {
				cout << costG[p][q] << endl;
			} else {
				cout << timeG[p][q] << endl;
			}
		}
	}
	re