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]
					t_newlen := t_dist[i][k] + t_dist[k][j]
					if c_newlen < c_dist[i][j] {
						c_dist[i][j] = c_newlen
						c_prev[i][j] = c_prev[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 <vector>
#include <set>
#include <map>
#include <list>
#include <iterator>
#include <queue>
#include <stack>
#include <deque>
#include <sstream>
#include <algorithm>
#include <numeric>
#include <string>
#include <cmath>
#include <complex>
#include <functional>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cassert>
#include <cstdlib>
#include <cctype>

#define REP(i,m,n) for(int i=m;i<(int)n;i++)
#define rep(i,n) for(int i=0;i<(int)n;i++)
#define rp(i,c) rep(i,(int)c.size())
#define fr(i,c) for(__typeof((c).begin()) i=(c).begin();i!=(c).end();i++)
#define mp make_pair
#define pb push_back
#define all(c) (c).begin(),(c).end()
#define rall(u) (u).rbegin(),(u).rend()
#define dbg(x) cerr<<#x<<" = "<<(x)<<endl
#define v_delete(a,b) (a).erase(remove((a).begin(), (a).end(), b), (a).end())
#define v_unique(a) (a).erase(unique((a).begin(), (a).end()), (a).end())
#define VV(T) vector<vector< T > >
#define init(a,b) memset((a), (b), sizeof((a)))
using namespace std;

typedef long long ll;
typedef vector<int> vi;
typedef pair<int,int> pii;
const int inf=1<<28;
const double INF=1e10,EPS=1e-9;


template<class T>int SIZE(T a){return a.size();}
template<class T>string IntToString(T num){string res;stringstream ss;ss<<num;return ss.str();}
template<class T>T StringToInt(string str){T res=0;for(int i=0;i<SIZE(str);i++)res=(res*10+str[i]-'0');return res;}
template<class T>T gcd(T a,T b){if(b==0)return a;return gcd(b,a%b);}
template<class T>T lcm(T a,T b){return a/gcd(a,b)*b;}

template <class T> void input(T& a, int n) { for (int i = 0; i < n; ++i) cin >> a[i]; }
template <class T> void input(T* a, int n) { for (int i = 0; i < n; ++i) cin >> a[i]; }

int in(){
	int t;
	cin >> t;
	return t;
}

struct sta{
	vi edges;
	vi costs;
	vi times;


};

int main()
{

	while(1){
		int n,m,k;
		cin >> n >> m;
		if(n==0 && m==0)
			break;
		vector<sta>stations(m);

		rep(i,n){
			int a,b,cost,time;
			cin >> a >> b >> cost >> time;
			a--;
			b--;
			stations[a].edges.pb(b);
			stations[a].costs.pb(cost);
			stations[a].times.pb(time);
			stations[b].edges.pb(a);
			stations[b].costs.pb(cost);
			stations[b].times.pb(time);
		}
		cin >> k;
		rep(i,k){
			int s,g,q;
			cin >> s >> g >> q;
			s--;
			g--;
			if(!q){
				queue<int> Q;
				vi cost(m,inf);
				cost[s]=0;
				Q.push(s);
				while(!Q.empty()){
					int f=Q.front();Q.pop();
					sta now=stations[f];
					rp(i,now.edges){
						int to=now.edges[i];
						int cos=now.costs[i];
						if(cost[to] > cost[f]+cos){
							cost[to]=cost[f]+cos;
							Q.push(to);
						}
					}
				}
				cout << cost[g] << endl;
			}else{
				queue<int> Q;
				vi time(m,inf);
				time[s]=0;
				Q.push(s);
				while(!Q.empty()){
					int f=Q.front();Q.pop();
					sta now=stations[f];
					rp(i,now.edges){
						int to=now.edges[i];
						int ti=now.times[i];
						if(time[to] > time[f]+ti){
							time[to]=time[f]+ti;
							Q.push(to);
						}
					}
				}
				cout << time[g] << endl;
			}
		}
	}
}

C++: #include <iostream>
#include <vector>
#include <string.h>
#include <time.h>

using namespace std;

static const int TYPE_COST =0;
static const int TYPE_TIME =1;

class station{
public:
	int cost;
	bool visited;
	vector<int> edge_to;
	vector<int> edge_cost;
	vector<int> edge_time;
	
	 public:
		station() :  cost(-1), visited(false){}
		void add_to(int to, int cost, int time)
		{
			this->edge_to.push_back(to);
			this->edge_cost.push_back(cost);
			this->edge_time.push_back(time);
		}
};

int dijkstra(station* sta, int size, int from, int to, int type);
void reset(station* sta, int size);

int main(int argc, char** argv)
{
	while( 1 ){
		int n, m, from, to, cost, time, type;
		cin >> n;
		cin >> m;
		if(n==0 && m==0) break;
		
		station sta[m];
		for(int i=0; i<m; i++){
			sta[i] = station();
		}
		
		for(int i=0; i<n; i++){
			cin >> from;
			cin >> to;
			cin >> cost;
			cin >> time;
			sta[from-1].add_to(to-1, cost, time);
			sta[to-1].add_to(from-1, cost, time);
		}
		cin >> n;
		for(int i=0; i<n; i++){
			cin >> from;
			cin >> to;
			cin >> type;
			clock_t t1 = clock();
			cout << dijkstra(sta, m, from-1, to-1, type) << endl;
			clock_t t2 = clock();
			//cout << "Time : "  << t2 - t1<< " (msec)" << endl;
			reset(sta, m);
		}
	}
	
	return 0;
}

int dijkstra(station* sta, int size, int start, int goal, int type)
{
	int to, cost;
	station done;
	vector<station> q;
	sta[start].cost = 0;
	q.push_back(sta[start]);
	
	while(!q.empty()){
		done = q[0];
		q.erase(q.begin());
		done.visited = true;
		
		vector<int>::iterator it_to = done.edge_to.begin();
		vector<int>::iterator it_cost = (type==TYPE_COST) ? done.edge_cost.begin() : done.edge_time.begin();
		while(it_to != done.edge_to.end()){
			to = *it_to;
			cost = done.cost + *it_cost;
			if(sta[to].cost < 0 || cost < sta[to].cost){
				sta[to].cost = cost;
				q.push_back(sta[to]);
			}
			
			++it_to;
			++it_cost;
		}
	}
	
	return sta[goal].cost;
}

void reset(station* sta, int size)
{
	for(int i=0; i<size; i++){
		sta[i].visited = false;
		sta[i].cost = -1;
	}
}