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<cstdio>
#include<vector>
#include<algorithm>

#define rep(i,n) for(int i=0;i<(n);i++)

using namespace std;

const int INF=1<<29;

template<class T>
class binary_heap{
	const static int N_MAX=3000;
	int n;
	T a[N_MAX+1];
public:
	binary_heap():n(0){}
	const T &find_min()const{ return a[1]; }
	void insert(const T &x){
		int u=++n;
		a[u]=x;
		while(u!=1 && a[u/2]>a[u]) swap(a[u/2],a[u]), u/=2;
	}
	void delete_min(){
		a[1]=a[n--];
		for(int u=1;2*u<=n;){
			int v=2*u;
			if(2*u+1<=n && a[2*u]>a[2*u+1]) v++;
			if(a[v]<a[u]) break;
			swap(a[v],a[u]);
			u=v;
		}
	}
	bool empty()const{ return n==0; }
	int size()const{ return n; }
};

struct edge{ int v,cost1,cost2; };

int main(){
	for(int m,n;scanf("%d%d",&m,&n),n;){
		vector<edge> G[100];
		rep(i,m){
			int u,v,cost1,cost2; scanf("%d%d%d%d",&u,&v,&cost1,&cost2); u--; v--;
			G[u].push_back((edge){v,cost1,cost2});
			G[v].push_back((edge){u,cost1,cost2});
		}

		int q; scanf("%d",&q);
		while(q--){
			int s,t,type; scanf("%d%d%d",&s,&t,&type); s--; t--;

			int d[100];
			rep(u,n) d[u]=(u==s?0:INF);
			static binary_heap< pair<int,int> > H; H.insert(make_pair(0,s));
			while(!H.empty()){
				int d_now=H.find_min().first,u=H.find_min().second;
				H.delete_min();

				if(d[u]<d_now) continue;

				rep(i,G[u].size()){
					const edge &e=G[u][i];
					int d2=d_now+(type==0?e.cost1:e.cost2);
					if(d[e.v]>d2){
						d[e.v]=d2;
						H.insert(make_pair(d2,e.v));
					}
				}
			}

			printf("%d\n",d[t]);
		}
	}

	return 0;
}

C++: #include<math.h>
#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#define REP(i,a,b) for(i=a;i<b;i++)
#define rep(i,n) REP(i,0,n)

using namespace std;
#define INF (1<<30)
int cost[200][200], time[200][200],dist[200];
int x[200][200];
bool vis[200];
int M,N;

void dij(int p, int q, int r){
	int i,j,k,l,m,n,mn;
	rep(i,M)rep(j,M)x[i][j]= (r==0)?cost[i][j]:time[i][j];
	rep(i,M)vis[i]=false,dist[i]=INF;
	dist[p-1]=0;
	for(;;){
		k=-1,mn=INF;
		rep(i,M)if(!vis[i]&&dist[i]<mn){mn=dist[i],k=i;}
		if(k==-1 || mn>=INF) break;
		if(k==q-1)break;
		vis[k]=true;
		rep(i,M)if(!vis[i])dist[i]=min(dist[i],dist[k]+x[k][i]);
	}
	cout<<dist[q-1]<<endl;
}

int main(){
	int i,j,k,l,m,n;
	
	while(cin>>N>>M){
		if((N|M)==0) break;

		rep(i,M){
			dist[i]=INF; 
		    rep(j,M){
			  if(i==j) {cost[i][j]=time[i][j]=0; continue;}
			  cost[i][j]=time[i][j]=INF;
			}
		}
		rep(i,N){//graph info
			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;
		}
		cin>>k;
		rep(i,k){//question
			int p,q,r;
			cin>>p>>q>>r;
			dij(p,q,r);
		}
	}
}

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

using namespace std;

#define INF 1e9

void wf(vector< vector<int> >& m) {
	int N = m.size();
	for (int i = 0; i < N; ++i) for (int j = 0; j < N; ++j) for (int k = 0; k < N; ++k) {
		m[i][j] = min(m[i][j], m[i][k] + m[k][j]);
	}
}

int main() {
	int n, N;
	while (cin >> n >> N, n || N) {
		vector< vector<int> > cost(N, vector<int>(N, INF));
		vector< vector<int> > time(N, vector<int>(N, INF));
		for (int i = 0; i < n; ++i) {
			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;
		}
		for (int i = 0; i < N; ++i) cost[i][i] = time[i][i] = 0;

		wf(cost);
		wf(time);

		int k; cin >> k;
		for (int t = 0; t < k; ++t) {
			int p, q, r; cin >> p >> q >> r; --p, --q;
			vector< vector<int> >& m = r == 0 ? cost : time;
			cout << m[p][q] << endl;
		}
	}
}