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 <sstream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <string>
#include <vector>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <bitset>
#include <numeric>
#include <climits>
#include <cfloat>
using namespace std;

class Edge
{
public:
    int to, cost;
    Edge(){};
    Edge(int to0, int cost0){to = to0; cost = cost0;}
};

void shortestPath(const vector<vector<Edge> >& edges, int start, vector<int>& dist)
{
    dist.assign(edges.size(), INT_MAX);
    dist[start] = 0;
    priority_queue<pair<int,int> ,vector<pair<int,int> >, greater<pair<int,int> > > q;
    q.push(make_pair(0, start));

    while(!q.empty()){
        pair<int, int> p = q.top();
        q.pop();
        int v = p.second;
        if(dist[v] < p.first)
            continue;
        for(unsigned i=0; i<edges[v].size(); ++i){
            Edge e = edges[v][i];
            if(dist[v] + e.cost < dist[e.to]){
                dist[e.to] = dist[v] + e.cost;
                q.push(make_pair(dist[e.to], e.to));
            }
        }
    }

    replace(dist.begin(), dist.end(), INT_MAX, -1);
}

int main()
{
    for(;;){
        int n, m;
        cin >> n >> m;
        if(n == 0)
            return 0;

        vector<vector<Edge> > cost(m+1);
        vector<vector<Edge> > time(m+1);
        for(int i=0; i<n; ++i){
            int a, b, x, y;
            cin >> a >> b >> x >> y;
            cost[a].push_back(Edge(b, x));
            cost[b].push_back(Edge(a, x));
            time[a].push_back(Edge(b, y));
            time[b].push_back(Edge(a, y));
        }

        int k;
        cin >> k;

        vector<vector<int> > minCost(m+1), minTime(m+1);
        for(int i=0; i<k; ++i){
            int p, q, r;
            cin >> p >> q >> r;
            if(r == 0){
                if(minCost[p].size() == 0)
                    shortestPath(cost, p, minCost[p]);
                cout << minCost[p][q] << endl;
            }else{
                if(minTime[p].size() == 0)
                    shortestPath(time, p, minTime[p]);
                cout << minTime[p][q] << endl;
            }
        }
    }
}

C++: ##include <iostream>
using namespace std;

const int INF = 1000000000;

int main()
{
  int count=0;
	while(count!=50){
		int n, m;
		cin >> n >> m;

		if(n==0 && m==0)
			break;

		 int C[100][100];
		 int T[100][100];
	   for(int i=0; i<m; i++){
		   for(int j=0; j<m; j++){
			   if(i==j){
	         C[i][j] = T[i][j] = 0;
		     }else{
			     C[i][j] = T[i][j] = INF;
		     }
		   }
     }

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

	     C[a-1][b-1] = C[b-1][a-1] = c;
		   T[a-1][b-1] = T[b-1][a-1] = t;
    }

    int k;
    cin>>k;
    for(int i=0;i<k;i++){
      int p, q, r;
      int a=0;
      cin>>p>>q>>r;
      int d[m][m];
      if(r==0){
        for(int i=0;i<m;i++){
          for(int j=0;j<m;j++){
            d[i][j]=C[i][j];
          }
        }
        for(int k=0;k<m;k++){
          for(int i=0;i<m;i++){
            for(int j=0;j<m;j++){
              if(d[i][j]>d[i][k]+d[k][j]){
                d[i][j]=d[i][k]+d[k][j];
              }
            }
          }
        }
        a=d[p-1][q-1];
        cout<<a<<endl;
      }
      if(r==1){
        for(int i=0;i<m;i++){
          for(int j=0;j<m;j++){
            d[i][j]=T[i][j];
          }
        }
        for(int k=0;k<m;k++){
          for(int i=0;i<m;i++){
            for(int j=0;j<m;j++){
              if(d[i][j]>d[i][k]+d[k][j]){
                d[i][j]=d[i][k]+d[k][j];
              }
            }
          }
        }
        a=d[p-1][q-1];
        cout<<a<<endl;
      }
    }
    count++;
	}

	return 0;
}

C++: #include <iostream>
#include <cstdio>
using namespace std;

#define rep(i,a) for(int i = 0 ; i < a ; i ++)
#define loop(i,a,b) for(int i = a ; i < b ; i ++)

int N,M;
int maze[110][110],tim[110][110];
int main(void){
	while(cin>>N>>M,N+M){
		rep(i,M)rep(j,M)maze[i][j] = tim[i][j] = (1<<29);
		while(N--){
			int a,b,c,t;
			cin>>a>>b>>c>>t;
			maze[--a][--b] = c;
			maze[b][a] = c;
			tim[a][b] = t;
			tim[b][a] = t;
		}
		rep(k,M){
			rep(i,M){
				rep(j,M){
					tim[i][j] = min(tim[i][j],tim[i][k] + tim[k][j]);
					maze[i][j] = min(maze[i][j],maze[i][k] + maze[k][j]);	
				}
			}
		}
		//rep(i,M)rep(j,M)cout<<tim[i][j]<<(j==M-1?'\n':' ');
		cin>>N;
		while(N--){
			int a,b,t;
			cin>>a>>b>>t;
			--a;--b;
			cout<<(t?tim[a][b]:maze[a][b])<<endl;
		}
	}
}

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

using namespace std;

int i, j, k, p, q, r, n, m, a, b, c, cost[101], t, dc[101][101], dt[101][101];

int dic(int d[101][101]) {
  cost[p] = 0;
  int min, f[101] = {};
  for(i = 0; i < m; i++) {
    f[p] = 1;
    for(j = 1; j <= m; j++) {
      if(f[j]) continue;
      if(cost[j] > cost[p] + d[p][j]) cost[j]  = cost[p] + d[p][j];
    }
    min = 200000000;
    for(j = 1; j <= m; j++ ) {
      if(f[j]) continue;
      if(min > cost[j]) min = cost[p = j];
    }
  }
  return cost[q];
}


int main() {
  for(i = 0; i <= 100; i++)
    for(j = 0; j <= 100; j++) {
      dc[i][j] = 100000000;
      dt[i][j] = 100000000;
    }
  
  cin >> n >> m;
  
  while(n--) {
    cin >> a >> b >> c >> t;
    dc[a][b] = dc[b][a] = c;
    dt[a][b] = dt[b][a] = t;
  }
  
  cin >> k;
  
  while(cin >> p  >> q, p != 0 || q != 0 ) {
    cin >> r;
    for(i = 0; i <= 100; i++) cost[i] = 1000000000;
    if(r) cout << dic(dt) << endl;
    else cout << dic(dc) << endl;
  }
  
  return 0;
}