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>
using namespace std;

const int INF = 1000000000;

int main()
{
  int count=0;
	while(count!=50){
		int n, m;
		cin >> n >> m;

		if(n==0 && m==0)
			break;

		 int C[100][100];
		 int T[100][100];
	   for(int i=0; i<m; i++){
		   for(int j=0; j<m; j++){
			   if(i==j){
	         C[i][j] = T[i][j] = 0;
		     }else{
			     C[i][j] = T[i][j] = INF;
		     }
		   }
     }

	   for(int i=0; i<n; i++){
		   int a, b, c, t;
		   cin >> a >> b >> c >> t;

	     C[a-1][b-1] = C[b-1][a-1] = c;
		   T[a-1][b-1] = T[b-1][a-1] = t;
    }

    int k;
    cin>>k;
    for(int i=0;i<k;i++){
      int p, q, r;
      int a=0;
      cin>>p>>q>>r;
      int d[m][m];
      if(r==0){
        for(int i=0;i<m;i++){
          for(int j=0;j<m;j++){
            d[i][j]=C[i][j];
          }
        }
        for(int k=0;k<m;k++){
          for(int i=0;i<m;i++){
            for(int j=0;j<m;j++){
              if(d[i][j]>d[i][k]+d[k][j]){
                d[i][j]=d[i][k]+d[k][j];
              }
            }
          }
        }
        a=d[p-1][q-1];
        cout<<a<<endl;
      }
      if(r==1){
        for(int i=0;i<m;i++){
          for(int j=0;j<m;j++){
            d[i][j]=T[i][j];
          }
        }
        for(int k=0;k<m;k++){
          for(int i=0;i<m;i++){
            for(int j=0;j<m;j++){
              if(d[i][j]>d[i][k]+d[k][j]){
                d[i][j]=d[i][k]+d[k][j];
              }
            }
          }
        }
        a=d[p-1][q-1];
        cout<<a<<endl;
      }
    }
    count++;
	}

	return 0;
}

C++: #include<iostream>
#include<algorithm>
using namespace std;
int main(){
  int n,m;
  while(cin >>n>>m,n||m){
    int c_t[100][100][2],ans[100][100][2];
    for(int i=0; i<100; i++){
      for(int j=0; j<100; j++){
	for(int k=0; k<2; k++){
	  ans[i][j][k] = 10000000;
	}
      }
    }
    for(int i=0,a,b,c,d; i<n; i++){
      cin >>a>>b>>c>>d;
      a--;b--;
      ans[a][b][0] = ans[b][a][0] = c;
      ans[a][b][1] = ans[a][b][1] = d;
    }
    for(int k=0; k<2; k++){
      for(int i=0; i<m; i++){
	for(int j=0; j<m; j++){
	  for(int l=0; l<m; l++){
	    ans[i][j][k] = min(ans[i][j][k],ans[i][l][k]+ans[l][j][k]);
	  }
	}
      }
    }
    int t=0;
    cin >>t;
    while(t--){
      int p,q,r;
      cin >>p>>q>>r;
      cout <<ans[p-1][q-1][r]<<endl;
    }
  }
  return 0;
}

C++: #include<iostream>
#include<algorithm>
using namespace std;

const int MAX=100;
const int INF=(1<<21);

int main(){

  int n,m;
  int a,b,cost,time;
  int p,q,r;
  int rail_cost[MAX][MAX];
  int rail_time[MAX][MAX];
  int k;
  while(1){
    cin>> n>> m;
    if(n==0 && m==0) break;
  
  for(int i=0;i<m;i++){
    for(int j=0;j<m;j++){
      rail_cost[i][j]=INF;
      rail_time[i][j]=INF;
    }
  }

  for(int i=0;i<n;i++){
    cin>> a>> b>> cost>> time; 
    rail_cost[a-1][b-1]=rail_cost[b-1][a-1]=cost;
    rail_time[a-1][b-1]=rail_time[b-1][a-1]=time;
  }

  for(int i=0;i<m;i++){
    for(int j=0;j<m;j++){
      for(int k=0;k<m;k++){
	rail_cost[j][k]=min(rail_cost[j][k],rail_cost[j][i]+rail_cost[i][k]);
	rail_time[j][k]=min(rail_time[j][k],rail_time[j][i]+rail_time[i][k]);
      }
    }
  }

  cin>> k;
  for(int i=0;i<k;i++){
    cin>> p>> q>> r;
    if(r==0){
      cout<< rail_cost[p-1][q-1]<< endl;
    }else{
      cout<< rail_time[p-1][q-1]<< endl;
    }
  }

  }
}

C++: #include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

struct Edge{
    int from,to,cost;
    Edge(int from,int to,int cost)
        : from(from),to(to),cost(cost) {};
};

const int INF = 1 << 30;
// s:始点,dist:距離,prev:最短経路木
bool bellman(const vector<vector<Edge> >& graph,int s,vector<int> &dist,vector<int> &prev){
    int n = graph.size();
    for(int i=0;i<n;i++) dist[i] = INF;
    dist[s] = 0;
    for(int i=0;i<n;i++) prev[i] = -1;

    bool neg_cycle = false;
    for(int i=0;i<n;i++){
        for(int j=0;j<n;j++){
            for(int k=0;k<graph[j].size();k++){
                Edge e = graph[j][k];
                if(dist[e.to] > dist[e.from] + e.cost){
                    dist[e.to] = dist[e.from] + e.cost;
                    prev[e.to] = e.from;
                    if(i == n-1){
                        dist[e.to] = -INF;
                        neg_cycle = true;
                    }
                }
            }
        }
    }
    return !neg_cycle;
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    while(true){
        int n,m;
        cin >> n >> m;
        if(n == 0 and m == 0) break;
        vector<vector<Edge> > C(m);
        vector<vector<Edge> > T(m);

        for(int i=0;i<n;i++){
            int a,b,cost,time;
            cin >> a >> b >> cost >> time;
            a--;b--;
            C[a].push_back(Edge(a,b,cost));
            C[b].push_back(Edge(b,a,cost));
            T[a].push_back(Edge(a,b,time));
            T[b].push_back(Edge(b,a,time));
        }
        int k;
        cin >> k;
        vector<int> dist(m);
        vector<int> prev(m);
        for(int i=0;i<k;i++){
            int p,q,r;
            cin >> p >> q >> r;
            p--,q--;
            if(r == 0){
                bellman(C,p,dist,prev);
            }else{
                bellman(T,p,dist,prev);
            }
            cout << dist[q] << endl;
        }
    }
    return 0;
}