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 <cstdio>
#include <cstdlib>
#include <cmath>
#include <climits>
#include <cfloat>
#include <map>
#include <utility>
#include <ctime>
#include <set>
#include <iostream>
#include <memory>
#include <string>
#include <cstring>
#include <vector>
#include <algorithm>
#include <functional>
#include <fstream>
#include <sstream>
#include <complex>
#include <stack>
#include <queue>
#include <cstring>
#include <numeric>
#include <cassert>
using namespace std;
#define rep(i, n) for (int(i) = 0; (i) < (n); (i)++)
class Timer
{
  private:
    double time_limit;
    //unsigned long long int cycle_per_sec = 2500000000; // Topcoder
    unsigned long long int cycle_per_sec = 2777777777; // AtCoder
    unsigned long long int beginCycle;
    unsigned long long int getCycle()
    {
        unsigned int low, high;
        __asm__ volatile("rdtsc"
                         : "=a"(low), "=d"(high));
        return ((unsigned long long int)low) | ((unsigned long long int)high << 32);
    }

  public:
    Timer(double time_limit) : time_limit(time_limit)
    {
        beginCycle = getCycle();
    }

    double elapsedTime()
    {

        return (double)(getCycle() - beginCycle) / cycle_per_sec;
    }
    bool isTLE()
    {
        return elapsedTime() >= time_limit;
    }
};

Timer gtimer(2.85);

int main()
{
    int m, n;
    while (cin >> m >> n && m)
    {
        int wf[2][110][110] = {};
        rep(i, 2) rep(j, 110) rep(k, 110)
            wf[i][j][k] = j == k ? 0 : 1e9;

        for (int i = 0; i < m; i++)
        {
            int a, b, c, t;
            cin >> a >> b >> c >> t;
            --a, --b;
            wf[0][a][b] = min(wf[0][a][b], c);
            wf[1][a][b] = min(wf[1][a][b], t);
            wf[0][b][a] = min(wf[0][a][b], c);
            wf[1][b][a] = min(wf[1][a][b], t);
        }
        rep(i, 2)
        {
            rep(j, 110) rep(k, 110) rep(l, 110)
            {
                wf[i][k][l] = min(wf[i][k][j] + wf[i][j][l], wf[i][k][l]);
            }
        }
        int Q;
        cin >> Q;
        while (Q--)
        {
            int a, b, c;
            cin >> a >> b >> c;
            --a, --b;
            cout << wf[c][a][b] << endl;
        }
    }
    std::cout.flush();
    return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <queue>
#include <bitset>
#include <set>
#include <map>
#include <stack>

#define rep(i,n) for(int i=0;i<n;i++)
#define REP(i,b,n) for(int i=b;i<n;i++)
#define SORT(c) sort((c).begin(),(c).end())
#define DESCSORT(c) sort(c.begin(), c.end(), greater<int>())

const float PI = 3.1415926;
static const int INFTY = (1<<30);

using namespace std;

typedef long long ll;
typedef long double ld;

int n, m, p, q, r;
int C[101][101], V[101][101];

void floyd() {
  rep(k,m) {
    rep(i,m) {
      if (C[i][k] == INFTY) continue;
      rep(j,m) {
        if (C[k][j] == INFTY) continue;
        C[i][j] = min(C[i][j], C[i][k] + C[k][j]);
      }
    }
  }
  rep(k,m) {
    rep(i,m) {
      if (V[i][k] == INFTY) continue;
      rep(j,m) {
        if (V[k][j] == INFTY) continue;
        V[i][j] = min(V[i][j], V[i][k] + V[k][j]);
      }
    }
  }
}

int main() {
  while(cin >> n >> m, n) {
    rep(i, m) rep(j, m) {
      C[i][j] = INFTY;
      V[i][j] = INFTY;
    }
    
    rep(i, n) {
      int tmp_i, tmp_j, ti, co;
      cin >> tmp_i >> tmp_j >> co >> ti;
      C[tmp_i-1][tmp_j-1] = co;
      V[tmp_i-1][tmp_j-1] = ti;
    }

    floyd();

    int k;
    cin >> k;

    rep(i,k) {
      cin >> p >> q >> r;
      if(r == 0)
        cout << C[p-1][q-1] << endl;
      else
        cout << V[p-1][q-1] << endl;
    }
  }
  
  return 0;
}

C++: #include <iostream>
const int MAX_E = 300, MAX_V = 100, INF = 1000000;
struct edge{int from, to, time, cost;};

edge es[MAX_E+1];
int d[MAX_V+1];
int n, m, k;

//0: time 1: cost
int minimum_value(int type, int start, int end){
	for(int i=0;i<=m;i++)d[i] = INF;
	d[start] = 0;

	int res = 0;
	while(true){
		bool update = false;
		for(int i=0;i<n;i++){
			edge e = es[i];
			int cost = type?e.cost:e.time;
			if(d[e.from] != INF && d[e.to] > d[e.from] + cost){
				d[e.to] = d[e.from] + cost;
				res = d[e.to];
				update = true;
			}		
		}
		if(!update)break;
	}

	return res;
}

int main(){
	while(std::cin >> n >> m, n){
		for(int i=0;i<n;i++){
			int from, to, time, cost;
			std::cin >> from >> to >> time >> cost;
			edge e;
			e.from = from, e.to = to, e.time = time, e.cost = cost;
			es[i] = e;
		}

		std::cin >> k;
		for(int j=0;j<k;j++){
			int start, end, type;
			std::cin >> start >> end >> type;
			std::cout << minimum_value(type, start, end) << std::endl;
		}
	}

	return 0;
}