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<cstring>
#include<algorithm>
#include<functional>
#include<iostream>
#include<queue>
#define rep(i,a,b) for(i=a;i<b;i++)
#define F1 first.first
#define F2 first.second
#define F3 second
#define INF 2100000000
#define long long int int
using namespace std;
typedef pair<pair<int,int>,int> P1;
typedef pair<int,int> P2;
int main(void)
{
	priority_queue<P2,vector<P2>,greater<P2> > que;
	int i,j,k,n,m,x,s,e;
	int a,b,cos,tim,st,en,way;
	int leng[1001],kami[1002];
	P1 glid1[6000],glid2[6000];
	P2 tori;
	while(1) {
		cin>>n>>m;
		if(n==0&&m==0) break;
		rep(i,0,n) {
			cin>>a>>b>>cos>>tim;
			glid1[i*2].F1=a,glid1[i*2].F2=b,glid1[i*2].F3=cos;
			glid2[i*2].F1=a,glid2[i*2].F2=b,glid2[i*2].F3=tim;
			glid1[i*2+1].F1=b,glid1[i*2+1].F2=a,glid1[i*2+1].F3=cos;
			glid2[i*2+1].F1=b,glid2[i*2+1].F2=a,glid2[i*2+1].F3=tim;
		}
		sort(glid1,glid1+n*2);sort(glid2,glid2+n*2);
		kami[1]=0;
		rep(i,1,n*2) {
			if(glid1[i].F1!=glid1[i-1].F1) {
				x=glid1[i].F1;
				kami[x]=i;
			}
		}
		kami[m+1]=n*2;
		
		cin>>k;
		rep(i,0,k) {
			cin>>st>>en>>way;
			for(j=1;j<=m;j++) leng[j]=INF;
			while(!que.empty()) que.pop();
			que.push(P2(0,st));
			while(!que.empty()) {
				tori=que.top(),que.pop();
				a=tori.first,b=tori.second;
				if(a<leng[b]) {
					leng[b]=a;
					if(b==en) break;
					s=kami[b],e=kami[b+1];
					if(way==0)rep(j,s,e) que.push(P2(a+glid1[j].F3,glid1[j].F2));
					else rep(j,s,e) que.push(P2(a+glid2[j].F3,glid2[j].F2));
				}
			}
			cout<<leng[en]<<endl;
		}
	}
	return 0;
}

C++: #include <iostream>
#include <vector>
#include <queue>
#define INF (int)1e9

int common_part(int m, int p, int q, std::vector<std::vector<std::pair<int, int> > > v); 
int bellman_ford(std::vector<std::vector<std::pair<int, int> > > v, std::vector<int> rvec); 

int main(void) {
    int n;
    int m;

    int a;
    int b;
    int cost;
    int time;

    int k;

    int p;
    int q;
    int r;

    int res;

    while (true) {
        std::cin >> n >> m;
        if (n == 0 && m == 0) {
            break; 
        }

        std::vector<std::vector<std::pair<int, int> > > vcost(m);
        std::vector<std::vector<std::pair<int, int> > > vtime(m);

        for (int i = 0; i < n; i++) {
            std::cin >> a >> b >> cost >> time;
            --a;
            --b;
            vcost[a].push_back(std::make_pair(cost, b));
            vcost[b].push_back(std::make_pair(cost, a));
            vtime[a].push_back(std::make_pair(time, b));
            vtime[b].push_back(std::make_pair(time, a));
        }

        std::cin >> k;

        for (int i = 0; i < k; i++) {
            std::cin >> p >> q >> r;
            --p;
            --q;

            // Bellman Ford or Dijkstra
            if (r == 0) {
                res = common_part(m, p, q, vcost);
            } else {
                res = common_part(m, p, q, vtime);
            }
            std::cout << res << std::endl;
        }
    }
    return 0;
}

void bellman_ford(int m, std::vector<std::vector<std::pair<int, int> > > &v, std::vector<int> &rvec, bool &flag) {
    int value;
    int target;

    for (int i = 0; i < m; i++) {
        for (int j = 0; j < v[i].size(); j++) {
            value = v[i][j].first;
            target = v[i][j].second;
            if (rvec[target] > rvec[i] + value) {
                rvec[target] = rvec[i] + value;
                flag = true;
            }
        }
    }
    return;
} 

int common_part(int m, int p, int q, std::vector<std::vector<std::pair<int, int> > > v) {
    std::vector<int> rvec(m, INF);
    bool flag;
    rvec[p] = 0;

    do{
        flag = false;
        bellman_ford(m, v, rvec, flag);

    } while(flag);

    return rvec[q];
}