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<cstdio>
#include<algorithm>
#include<queue>

#define INF 1<<29

class state{
	public:
	int p,v;
	state(){}
	state(int a,int b){
		p=a;v=b;
	}
	bool operator < (const state &a) const{
		return v > a.v;
	}
};
using namespace std;

int main(){
	while(1){
		int n,m;
		scanf("%d%d",&m,&n);
		if(n==0 && m==0){
			break;
		}
		int cost[101][101];
		int time[101][101];
		
		for(int i=0;i<101;i++)
		for(int j=0;j<101;j++)
		cost[i][j]=time[i][j]=INF;
		
		for(int i=0;i<m;i++){
			int a,b,c,d;
			scanf("%d%d%d%d",&a,&b,&c,&d);
			cost[a][b]=cost[b][a]=c;
			time[a][b]=time[b][a]=d;
		}
		
		scanf("%d",&m);
		for(int i=0;i<m;i++){
			int st,en,va;
			scanf("%d%d%d",&st,&en,&va);
			
			priority_queue<state> aa;
			
			int meen[101];
			int visit[101]={0};
			
			for(int i=0;i<101;i++){meen[i]=INF;}
			
			aa.push(state(st,0));
			meen[st]=0;
			int ans=0;
			while(1){
				state u = aa.top();
				aa.pop();
				
				if(u.p==en){
					ans=u.v;
					break;
				}
				
				visit[u.p]=1;
				
				for(int i=1;i<=n;i++){
					if(visit[i]==0){
						int val=cost[i][u.p];
						if(va==1){
							val=time[i][u.p];
						}
						if(val+u.v < meen[i]){
							meen[i]=val+u.v;
							aa.push(state(i,meen[i]));
						}
					}
				}
			}
			printf("%d\n",ans);
		}
	}
}

C++: #include<iostream>
#include<math.h>
#include<string>
#include<vector>
#include<algorithm>
#include<queue>
using namespace std;
#define INF 1<<30

struct edge{
	int to;
	int cost;
	edge() {};
	edge(int a, int b) {
		to = a;
		cost = b;
	}
};

struct Node {
	int pos;
	int cost;
	Node() {};
	Node(int a, int b) {
		pos = a;
		cost = b;
	}
	bool operator <(const Node& rhs) const {
		return cost > rhs.cost;
	}
};

void dijkistra(int st, int TO,int V,vector<vector<edge> >& graph) {
	priority_queue<Node> q;
	vector<int> d(V);
	for (int i = 0;i < V;i++) {
		d[i] = INF;
	}
	d[st] = 0;
	q.push(Node(st, 0));
	while (!q.empty()) {
		Node s = q.top(); q.pop();
		int pos = s.pos;
		for (int i = 0;i < graph[pos].size();i++) {
			int to = graph[pos][i].to;
			int cost = graph[pos][i].cost;
			if (d[pos] + cost < d[to]) {
				d[to] = d[pos] + cost;
				q.push(Node(to, d[to]));
			}

		}
	}
	cout << d[TO] << endl;


}
int partition(int A[],int p, int r) {
	int x = A[r];
	int i = p - 1;
	for (int j = p;j < r;j++) {
		if (x >= A[j]) {
			i = i + 1;
			swap(A[i], A[j]);
		}
	}
		swap(A[i + 1], A[r]);
		return i + 1;
}
void quicksort(int A[], int p, int r) {
	if (p < r) {
		int q = partition(A, p, r);
		quicksort(A, p, q-1);
		quicksort(A, q + 1, r);
	}
}

int getNumberOfCoin(int C[],int n,int m) {
	int T[50000];
	for (int j = 0;j <= n;j++) {
		T[j] = INF;
	}
	T[0] = 0;
	for (int i = 0;i < m;i++) {
		for (int j = 0;j <= n;j++) {
			if (j - C[i] >=0  ) {
				T[j] = min(T[j], T[j - C[i]] + 1);
			}
		}
	}
	return T[n];
}
int knapsack(int w, int n,int* v,int* ww) {
	int W[101][10001];
		for (int j = 0;j <= w;j++) {
			W[0][j] = 0;
		}
	for (int i = 0;i < n;i++) {
		for (int k = 0;k < n;k++){
			for (int j = 0;j <= w;j++) {
				if (j - ww[k] < 0) {
					W[i + 1][j] = W[i][j];
				}
				if (j - ww[i] >= 0) {
					W[i + 1][j] = max(W[i][j], W[i][j - ww[k]] + v[k]);

				}
			}
		}
	}
	return W[n][w];
}
int main() {
	int line, num;
	cin >> line >> num;
	vector<vector<edge> > COST(num);
	vector<vector<edge> > TIME(num);
	for (int i = 0;i < line;i++) {
		int a, b, cost, time;
		cin >> a>>b>>cost>>time;
		COST[a-1].push_back(edge(b-1, cost));
		COST[b-1].push_back(edge(a-1, cost));
		TIME[a-1].push_back(edge(b-1, time));
		TIME[b-1].push_back(edge(a-1, time));
	}
	int k;
	cin >> k;
	for (int i = 0;i < k;i++) {
		int p, q, r;
		cin >> p >> q >> r;
		if (r == 0) {
			dijkistra(p-1, q-1, num, COST);
		}
		else if (r == 1) {
			dijkistra(p-1, q-1, num, TIME);
		}
	}
	int n1, n2;
	cin >> n1 >> n2;
	return 0;
	
}

int isPrime(int x) {
	if (x <= 1) return false;
	if (x>2 && x % 2 == 0) return false;
	for (int i = 2;i <= sqrt(x);i++) {
		if (x%i == 0) {
			return false;
		}
	}
	if (x == 2) return true;
	return true;
}

C++: #include<iostream>
#include<string.h>
#include<vector>
#include<list>
#include<stdio.h>
#include<math.h>
#include<iomanip>
#include<map>
#include<stack>
#include<queue>
#define range(i,a,b) for(int i = (a); i < (b); i++)
#define rep(i,b) range(i,0,b)
#define debug(x) cout << "debug " << x << endl;
using namespace std;

int dp[3005][3005][2], n, m;

void solve(int dp[][3005][2], int st, int en, int d){
    rep(i, n){
        rep(j, n){
            rep(k, n){
                dp[i][j][d] = min(dp[i][k][d] + dp[k][j][d], dp[i][j][d]);
            }
        }
    }
}

int main(){
    int k;
    int a, b, c, d;
    int st, en, de;
    rep(i, 3005)
        rep(j, 105)
            rep(k, 2)
                dp[i][j][k] = 2 << 24;

    while(cin >> n >> m, n||m){
        rep(i, n){
            cin >> a >> b >> c >> d;
            dp[a][b][0] = c; dp[b][a][0] = c;
            dp[a][b][1] = d; dp[b][a][1] = d;
        }
        cin >> k;
        rep(i, k){
            cin >> st >> en >> de;
            solve(dp, st, en, de);
            cout << dp[st][en][de] << endl;
        }
    }
}