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 <queue>
using namespace std;
struct Line{
        int a;
        int b;
        int cost;
        int time;
};
int Min(int x,int y){
        return x<y?x:y;
}
#define Max 2000000000
int main(){
        int N,M;
        while(true){
                Line lines[3000];
                cin >> N >>M;
                if(N+M==0)      break;
                for(int i=0 ; i<N ; i++ ){
                        cin >> lines[i].a >> lines[i].b ;
                        cin >> lines[i].cost >> lines[i].time;
                }
                int K;
                cin >> K;
                for(int i=0 ; i<K ; i++ ){
                        int to,from,r;
                        cin >> from >> to>>r;
                        queue <int> circle;
                        circle.push(from);
                        int dp[3000];
                        for(int i=0 ; i<=M ; i++ )
                                dp[i]=Max;
                        dp[from]=0;
                        while(circle.size()!=0){
                                int now=circle.front();
                                for(int i=0 ; i<N ; i++ ){
                                        if(now==lines[i].a){
                                                int next=lines[i].b;
                                                if(!r)
                                                        dp[next]=Min(dp[next],dp[now]+lines[i].cost);
                                                else
                                                        dp[next]=Min(dp[next],dp[now]+lines[i].time);
                                                circle.push(lines[i].b);
                                        }
                                }
                                circle.pop();
                        }
                        cout << dp[to] << endl;
                }
        }
        return 0;
}

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

constexpr int MAX_N = 100, INF = (int)1e8;

using P = std::pair<int, int>;

struct edge {
	int to, cost;
	edge() = default;
	edge(int _t, int _c) : to(_t), cost(_c) {}
};

int n;
std::vector<edge> G[2][MAX_N];//0:??????,1:??????

int d[MAX_N];

int dijkstra(int s, int g, int index) {
	std::fill(d, d + n, INF);
	d[s] = 0;
	std::priority_queue<P, std::vector<P>, std::greater<P>> que;
	que.emplace(d[s], s);
	while (!que.empty()) {
		P p = que.top();
		que.pop();
		if (p.second == g)
			return d[g];
		if (d[p.second] > p.first)
			continue;
		for (int i = 0; i < G[index][p.second].size(); ++i) {
			edge e = G[index][p.second][i];
			if (d[e.to] > d[p.second] + e.cost) {
				d[e.to] = d[p.second] + e.cost;
				que.emplace(d[e.to], e.to);
			}
		}
	}
	return -1;
}

int main() {
	while (1) {
		int m;
		std::cin >> m >> n;
		if (m + n == 0)
			break;
		int a, b, c, t;
		for (int i = 0; i < m; ++i) {
			std::cin >> a >> b >> c >> t;
			--a;
			--b;
			G[0][a].emplace_back(b, c);
			G[0][b].emplace_back(a, c);
			G[1][a].emplace_back(b, t);
			G[1][b].emplace_back(a, t);
		}
		int q, r;
		std::cin >> q;
		int p[2];
		for (int i = 0; i < q; ++i) {
			std::cin >> p[0] >> p[1] >> r;
			--p[0];
			--p[1];
			std::cout << dijkstra(p[0], p[1], r) << std::endl;
		}
		for (int i = 0; i < 2; ++i) {
			for (int j = 0; j < n; ++j)
				G[i][j].clear();
		}
	}
	return 0;
}