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<algorithm>
#define MAX_M 301
#define MAX_N 301
#define MAX_K 301
#define MAX_INT 1 << 29;
using namespace std;

//dx[wa][wb][XCb`(0:àz, 1:Ô)] = (waÆwbÔÌàz or Ô)
int dx[MAX_N][MAX_N][2];

//p©çqÜÅÌÅ¬àzðÔ·
int tellcost(int p, int q, int n, int m);

//p©çqÜÅÌÅZÔðÔ·
int telltime(int p, int q, int n, int m);

int main(){
	//n = üHÌîñÌ, m = wÌ
	int n, m;
	
	//üHÌîñðüÍ
	while(cin >>n >>m){
		if(n == 0 && m == 0) break;
		
		//dx[][][]Ìú»(SÄ-1É·é)
		for(int i = 0; i < MAX_N; i++){
			for(int j = 0; j < MAX_N; j++){
				dx[i][j][0] = -1;
				dx[i][j][1] = -1;
			}
		}
		
		for(int i = 0; i < n; i++){
			
			//a = wa, b = wb, cost = wa©çwbÜÅÌàz, time = wa©çwbÜÅÌÔ
			int a, b, cost, time;
			
			cin >>a >>b >>cost >>time;
			dx[a][b][0] = cost;
			dx[a][b][1] = time;
		}
		
		//k = â¢í¹Ì
		int k;
		
		cin >>k;
		for(int i = 0; i < k; i++){
			
			//p = o­w, q = w, r = oÍ·élÌíÞ, ans = Ö©çAÁÄ«½lðüêéÏ(±êª¦)
			int p, q, r, ans;
			cin >>p >>q >>r;
			
			//oÍ·élÌíÞª0(Å¬àz)Èç
			if(r == 0){
				ans = tellcost(p, q, n, m);
			
			//oÍ·élÌíÞª1(ÅZÔ)Èç
			} else{
				ans = telltime(p, q, n, m);
			}
			cout <<ans <<endl;
		}
	}
	return 0;
}

int tellcost(int p, int q, int n, int m){
	
	//checkendnum[wÌÔ] = Å¬àz(¢mèÌêÍMAX_INT)
	int checkendnum[MAX_N];
	
	//checkendi[wÌÔ] = Å¬àzªmèµ½©Ç¤©(false:¢mè, true:mè)
	bool checkendi[MAX_N] = {false};
	
	//checkendnum[1 ` MAX_N]ðMAX_INTÅú»
	for(int i = 0; i < MAX_N; i++){
		checkendnum[i] = MAX_INT;
	}
	
	//p = ¡²×Ä¢ém[h
	int node = p;
	
	//o­wÍà¤0ÅmèµÄ¢é
	checkendnum[node] = 0;
	checkendi[node] = true;
	
	//EoðÍmè³ê½m[h = q
	while(1){
		
		//SÄÌüHÌîñð²×é
		for(int i = 0; i < n; i++){
			
			//p©çiÉs­àzÌîñª èA»êªmèµÄ¢È¯êÎ
			if(dx[node][i][0] != -1){
				if(checkendi[i] == false){
					
					//¡ÜÅiÌm[hÉüÁÄ¢½îñÆAVµ­XV³êéûÌA¬³¢ûðóâÆ·é
					checkendnum[i] = min(checkendnum[i], (dx[node][i][0] + checkendnum[node]));
				}
			
			//p©çiÉs­àzÌîñª èA»êªmèµÄ¢È¯êÎ
			} else if(dx[i][node][0] != -1){
				if(checkendi[i] == false){
					
					//¡ÜÅiÌm[hÉüÁÄ¢½îñÆAVµ­XV³êéûÌA¬³¢ûðóâÆ·é
					checkendnum[i] = min(checkendnum[i], (dx[i][node][0] + checkendnum[node]));
				}
			}
		}
		//minnum = mèµÄ¢È¢wÌÅAÅ¬Ìàz, mini = minnumðÂwÌÔ
		int minnum = MAX_INT;
		int mini = -1;
		
		//SÄÌwð²×é
		for(int i = 1; i <= m; i++){
			
			//àzªmèµÄ¨ç¸Aminnumæè¬³¢àzðÂÈç
			if(checkendi[i] == false && checkendnum[i] < minnum){
				minnum = checkendnum[i];
				mini = i;
			}
		}
		
		//miniÌwÌàzðmè
		checkendi[mini] = true;
		
		//Ì²×ém[hðminiÉ·é
		node = mini;
		
		//qÌÅ¬àzªmèµ½ÈçI¹(I¹ð)
		if(checkendi[q] == true){
			break;
		}
	}
	return checkendnum[q];
}

int telltime(int p, int q, int n, int m){
	
	//checkendnum[wÌÔ] = ÅZÔ(¢mèÌêÍMAX_INT)
	int checkendnum[MAX_N];
	
	//checkendi[wÌÔ] = ÅZÔªmèµ½©Ç¤©(false:¢mè, true:mè)
	bool checkendi[MAX_N] = {false};
	
	//checkendnum[1 ` MAX_N]ðMAX_INTÅú»
	for(int i = 0; i < MAX_N; i++){
		checkendnum[i] = MAX_INT;
	}
	
	//p = ¡²×Ä¢ém[h
	int node = p;
	
	//o­wÍà¤0ÅmèµÄ¢é
	checkendnum[node] = 0;
	checkendi[node] = true;
	
	//EoðÍmè³ê½m[h = q
	while(1){
		
		//SÄÌüHÌîñð²×é
		for(int i = 0; i < n; i++){
			
			//p©çiÉs­ÔÌîñª èA»êªmèµÄ¢È¯êÎ
			if(dx[node][i][1] != -1){
				if(checkendi[i] == false){
					
					//¡ÜÅiÌm[hÉüÁÄ¢½îñÆAVµ­XV³êéûÌA¬³¢ûðóâÆ·é
					checkendnum[i] = min(checkendnum[i], (dx[node][i][1] + checkendnum[node]));
				}
			
			//p©çiÉs­àzÌîñª èA»êªmèµÄ¢È¯êÎ
			} else if(dx[i][node][1] != -1){
				if(checkendi[i] == false){
					
					//¡ÜÅiÌm[hÉüÁÄ¢½îñÆAVµ­XV³êéûÌA¬³¢ûðóâÆ·é
					checkendnum[i] = min(checkendnum[i], (dx[i][node][1] + checkendnum[node]));
				}
			}
		}
		//minnum = mèµÄ¢È¢wÌÅAÅZÌÔ, mini = minnumðÂwÌÔ
		int minnum = MAX_INT;
		int mini = -1;
		
		//SÄÌwð²×é
		for(int i = 1; i <= m; i++){
			
			//ÔªmèµÄ¨ç¸AminnumæèZ¢ÔðÂÈç
			if(checkendi[i] == false && checkendnum[i] < minnum){
				minnum = checkendnum[i];
				mini = i;
			}
		}
		
		//miniÌwÌÔðmè
		checkendi[mini] = true;
		
		//Ì²×ém[hðminiÉ·é
		node = mini;
		
		//qÌÅZÔªmèµ½ÈçI¹(I¹ð)
		if(checkendi[q] == true){
			break;
		}
	}
	return checkendnum[q];
}

C++: 
#include <bits/stdc++.h>
#define r(i,n) for(int i=0;i<n;i++)
#define INF 1<<29
using namespace std;
main(){
  int m,n;
  while(cin>>m>>n,n){
    int a1[n][n],a2[n][n],q,w,e,r;
    r(i,n)r(j,n){
      if(i==j)a2[i][j]=a1[i][j]=0;
      else a2[i][j]=a1[i][j]=INF;
    }
    while(m--){
      scanf("%d%d%d%d",&q,&w,&e,&r);q--;w--;
      a1[q][w]=a1[w][q]=e;
      a2[q][w]=a2[w][q]=r;
    }
    r(k,n)
    #pragma omp parallel
    r(i,n)
    #pragma omp parallel
    r(j,n){
      a1[i][j]=min(a1[i][j],a1[i][k]+a1[k][j]);
      a2[i][j]=min(a2[i][j],a2[i][k]+a2[k][j]);
    }
    cin>>e;
    while(e--){
      scanf("%d%d%d",&q,&w,&r);q--;w--;
      if(r)cout<<a2[q][w]<<endl;
      else cout<<a1[q][w]<<endl;
    }
  }
}