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<algorithm>

using namespace std;

int main(void){
	int floy[101][101][2];
	while(1){
		int n,m;
		scanf("%d%d",&n,&m);
		if(n==0&&m==0){
			break;
		}
		for(int b=0;b<2;b++){
			for(int i=0;i<=m;i++){
				for(int j=0;j<=m;j++){
					floy[i][j][b]=99999;
				}
			}
		}
		
		for(int i=0;i<n;i++){
			int a,b,cost,time;
			scanf("%d%d%d%d",&a,&b,&cost,&time);
			floy[a][b][0]=cost;
			floy[b][a][0]=cost;
			floy[a][b][1]=time;
			floy[b][a][1]=time;
		}
		
		for(int b=0;b<2;b++){
			for(int i=1;i<=m;i++){
				for(int j=1;j<=m;j++){
					for(int k=1;k<=m;k++){
						floy[i][j][b]=min(floy[i][j][b],floy[i][k][b]+floy[k][j][b]);
					}
				}
			}
		}
		
		int kazu;
		scanf("%d",&kazu);
		
		for(int i=0;i<kazu;i++){
			int a,b,c;
			scanf("%d%d%d",&a,&b,&c);
			printf("%d\n",floy[a][b][c]);
		}
	}
}

C++: #include<queue>
#include<cstdio>
#include<algorithm>

#define rep(i,n) for(int i=0;i<(n);i++)

using namespace std;

// #include"binary_heap.cpp"
// #include"d_heap.cpp"
// #include"pqueue.cpp"

template<class T>
class d_heap_for_Dijkstra{
	static const int N_MAX=1000;
	int n,d,key[N_MAX],pos[N_MAX];
	T val[N_MAX];

	void sift_up(int i,const T &x){
		val[i]=x;
		while(i!=0 && val[(i-1)/d]>val[i]){
			int p=(i-1)/d;
			swap(pos[key[p]],pos[key[i]]);
			swap(key[p],key[i]);
			swap(val[p],val[i]);
			i=p;
		}
	}
	void sift_down(int i,const T &x){
		val[i]=x;
		for(int j,k,c;;i=j){
			j=i;
			for(c=0,k=d*i+1;c<d;c++,k++) if(k<n && val[j]>val[k]) j=k;
			if(j==i) break;
			swap(pos[key[j]],pos[key[i]]);
			swap(key[j],key[i]);
			swap(val[j],val[i]);
		}
	}
public:
	d_heap_for_Dijkstra(int d):n(0),d(d){}
	int find_min()const{ return key[0]; }
	void insert(int u,const T &x){
		int i=n++;
		key[i]=u;
		pos[u]=i;
		sift_up(i,x);
	}
	void delete_min(){
		n--;
		key[0]=key[n];
		sift_down(0,val[n]);
	}
	void decrease_key(int u,const T &x){
		sift_up(pos[u],x);
	}
	bool empty()const{ return n==0; }
	int size()const{ return n; }
	// bool member(int u)const{ return pos[u]}
	void print(){
		puts("-------");
		printf("n=%d:\n",n);
		rep(i,n) printf("  key[%d] = %d, val[%d] = %d\n",i,key[i],i,val[i]);
		rep(i,5) printf("  pos[%d] = %d\n",i,pos[i]);
		puts("-------");
	}
};

const int INF=1<<29;

struct edge{ int v,cost1,cost2; };

int main(){
	for(int m,n;scanf("%d%d",&m,&n),n;){
		vector<edge> G[100];
		rep(i,m){
			int u,v,cost1,cost2; scanf("%d%d%d%d",&u,&v,&cost1,&cost2); u--; v--;
			G[u].push_back((edge){v,cost1,cost2});
			G[v].push_back((edge){u,cost1,cost2});
		}

		int q; scanf("%d",&q);
		while(q--){
			int s,t,type; scanf("%d%d%d",&s,&t,&type); s--; t--;
// printf("s=%d, t=%d\n",s+1,t+1);

			int d[100];
			rep(u,n) d[u]=(u==s?0:INF);
			d_heap_for_Dijkstra<int> H(4);
			H.insert(s,0);
			while(!H.empty()){
// H.print();
				int u=H.find_min();
// printf("  u=%d, d[%d]=%d\n",u,u,d[u]);
				H.delete_min();

				rep(i,G[u].size()){
					const edge &e=G[u][i];
					int d2=d[u]+(type==0?e.cost1:e.cost2);
					if(d[e.v]>d2){
// printf("    v=%d, d2=%d\n",e.v,d2);
						if(d[e.v]==INF) H.insert(e.v,d2);
						else            H.decrease_key(e.v,d2);
						d[e.v]=d2;
					}
				}
			}

			printf("%d\n",d[t]);
		}
	}

	return 0;
}

C++: #include <iostream>


#define MAX_M 110
#define INF   10000

int n, m, k;
int ct[MAX_M][MAX_M];
int tm[MAX_M][MAX_M];
int d[MAX_M][MAX_M];
int e[MAX_M][MAX_M];

void warshall_floyd() {
    for (int k=1; k<=m; k++) {
        for (int i=1; i<=m; i++) {
            for (int j=1; j<=m; j++) {
                ct[i][j] = std::min(ct[i][j], ct[i][k] + ct[k][j]);
                tm[i][j] = std::min(tm[i][j], tm[i][k] + tm[k][j]);
            }
        }
    }
}

int main() {
    while (true) {
        std::cin >> n >> m;
        if (!n && !m) break;
        for (int i=1; i<=m; i++) {
            for (int j=1; j<=m; j++) {
                ct[i][j] = INF;
                tm[i][j] = INF;
                if (i == j) {
                    ct[i][j] = 0;
                    tm[i][j] = 0;
                }
            }
        }

        for (int i=0; i<n; i++) {
            int a, b, c, t;
            std::cin >> a >> b >> c >> t;
            ct[a][b] = c;   ct[b][a] = c;
            tm[a][b] = t;   tm[b][a] = t;
        }
        warshall_floyd();

        std::cin >> k;
        for (int i=0; i<k; i++) {
            int p, q, r;
            std::cin >> p >> q >> r;
            if (r == 0) {
                std::cout << ct[p][q] << std::endl;
            } else {
                std::cout << tm[p][q] << std::endl;
            }
        }
    }
    return 0;
}