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<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);
		G1.clear();
		G2.clear();
		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++: #include <iostream>
#include <cstring>
using namespace std;

const int INF = 1000000;
const int MAX_V = 101;

int cost[MAX_V][MAX_V];
int time[MAX_V][MAX_V];
int d[MAX_V];
bool used[MAX_V];
int V;

int n,m;

void dijkstra(int s,bool r){
    fill(d,d+m,INF);
    memset(used,false,sizeof(used));
    d[s]=0;
    while(1){
        int v=-1;
        for(int u=0;u<m;u++){
            if(used[u]) continue;
            if(v==-1||d[u]<d[v]){
                v=u;
            }
        }
        if(v==-1) break;
        used[v]=true;
        for(int u=0;u<m;u++){
            int c;
            if(r) c=cost[u][v];
            else c=time[u][v];
            d[u]=min(d[u],d[v]+c);
        }
    }
}
int main(){
    while(cin >> n >> m,n+m){
        for(int i=0;i<m+1; i++){
            for(int j=0; j<m; j++){
                cost[i][j]=INF;
                time[i][j]=INF;
            }
        }
        for (int i = 0; i < m+1; ++i) {
            cost[i][i]=0;
            time[i][i]=0;
        }
        for (int i = 0; i < n; ++i) {
            int to,from,c,t;
            cin >> to>>from>>c>>t;
            to--; from--;
            cost[to][from]=c;
            cost[from][to]=c;
            time[to][from]=t;
            time[from][to]=t;
        }
        int k; cin>>k;
        for (int i = 0; i < k; ++i) {
            int p,q,r;
            cin>>p>>q>>r;
            p--; q--;
            dijkstra(p,!r);
            cout<<d[q]<<endl;
        }
    }
}

C++: #include <iostream>
#include <vector>
#include <utility>
#include <queue>
#define INF 1000000
using namespace std;
typedef pair<int, int> P;
struct line {
  int to,time,cost;
};

vector<line> L[100];
int costv[100];
int timev[100];

void mincost(int from,int to) {
  priority_queue<P, vector<P>, greater<P> > que;
  for(int i=0;i<100;i++) {
    costv[i] = INF;
  }
  costv[from] = 0;
  que.push(P(0,from));
  while(!que.empty()) {
    P p = que.top(); que.pop();
    int v = p.second;
    if(costv[v] < p.first) continue;
    for(int i=0;i < L[v].size();i++) {
      line l = L[v][i];
      if(costv[l.to] > costv[v] + l.cost) {
	costv[l.to] = costv[v] + l.cost;
	que.push(P(costv[l.to], l.to));
      }
    }
  }
  cout << costv[to] << endl;
}

void mintime(int from,int to) {
  priority_queue<P, vector<P>, greater<P> > que;
  for(int i=0;i<100;i++) {
    timev[i] = INF;
  }
  timev[from] = 0;
  que.push(P(0,from));
  while(!que.empty()) {
    P p = que.top(); que.pop();
    int v = p.second;
    if(timev[v] < p.first) continue;
    for(int i=0;i < L[v].size();i++) {
      line l = L[v][i];
      if(timev[l.to] > timev[v] + l.time) {
	timev[l.to] = timev[v] + l.time;
	que.push(P(timev[l.to], l.to));
      }
    }
  }
  cout << timev[to] << endl;
}

int main() {
  int n,m,k;
  while(cin >> n >> m) {
    if(n==0&&m==0)break;
    for(int i=0;i<100;i++) {
      L[i].clear();
    }
    for(int i=0;i<n;i++) { //input line
      line temp;
      int f,t,ti,co;
      cin >> f >> t >> co >> ti;
      temp.to = t;
      temp.time = ti;
      temp.cost = co;
      L[f].push_back(temp);
      temp.to = f;
      L[t].push_back(temp);
    }

    cin >> k;
    for(int i=0;i<k;i++) {
      int p,q,r;
      cin >> p >> q >> r;
      if(r == 0)
	mincost(p,q);
      else
	mintime(p,q);
    }
  }
}