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<stdio.h>
#include<algorithm>
#include <map>
#include<stdio.h>
#include<algorithm>
#include <map>
#include <list>
#include <stack>
#include <queue>
#include <map>
#include <vector>
#include <iostream>
#include <functional>
#include <time.h>
using namespace std;
clock_t fi, endtime;

const int INF = 100 * 1000 + 2;
const int r_c = 0;
const int r_t = 1;
const int MAX_V = 100;
const int MAX_E = 6000;

int n, m, a, b, c, t;
int k, p, q, r;
int wf[MAX_V][2] = { 0 };

struct edge { int from, to, ct[2]; };
edge edg[MAX_E];

int main()
{
	scanf("%d %d", &n, &m);
	for (int i = 0; i <= m * 2; ++i) {
		scanf("%d %d %d %d", &a, &b, &c, &t);
		edg[i].from = a - 1; edg[i].to = b - 1; edg[i].ct[r_c] = c; edg[i].ct[r_t] = t;
		++i;
		edg[i].from = b - 1; edg[i].to = a - 1; edg[i].ct[r_c] = c; edg[i].ct[r_t] = t;
	}
	scanf("%d", &k);
	for (int i = 0; i < k; ++i) {
		scanf("%d %d %d", &p, &q, &r);
		for (int i = 0; i < n; ++i) {
			wf[i][r] = INF;
		}
		wf[p - 1][r] = 0;
		while (1) {
			bool bo = false;
			for (int i = 0; i < m * 2; ++i) {
				edge e = edg[i];
				if (wf[e.from][r] != INF && wf[e.to][r] > wf[e.from][r] + e.ct[r]) {
					wf[e.to][r] = wf[e.from][r] + e.ct[r];
					bo = true;
				}
			}
			if (!bo) break;
		}
		if (wf[q - 1][r] == INF) printf("INF\n");
		else printf("%d\n", wf[q - 1][r]);
	}
}

C++: #include<iostream>
#include<queue>
#include<algorithm>
#include<vector>
using namespace std;
typedef pair<int,int> P;
int D[440];
int n,m,x,y,cost,Time,p,q,r;
vector<P> matrix1[440],matrix2[440];
void djkstra1(int s){ 
    priority_queue<P,vector<P>,greater<P> > que;
    for(int i=0;i<n+2;i++)D[i] = 10000000;
    D[s] = 0;
    que.push(P(s,0));

    while(!que.empty() ){
      P p = que.top();que.pop();
      int v = p.first;
      if(D[v] < p.second)continue;
      for(int i=0;i<matrix1[v].size();i++){
	P pp = matrix1[v][i];
	if(D[pp.first] > D[v] + pp.second){
	  D[pp.first] = D[v] + pp.second;
	  que.push(P(pp.first,D[pp.first]));
	}
      }
    }
}

void djkstra2(int s){ 
    priority_queue<P,vector<P>,greater<P> > que;
    for(int i=0;i<n+2;i++)D[i] = 10000000;
    D[s] = 0;
    que.push(P(s,0));

    while(!que.empty() ){
      P p = que.top();que.pop();
      int v = p.first;
      if(D[v] < p.second)continue;
      for(int i=0;i<matrix2[v].size();i++){
	P pp = matrix2[v][i];
	if(D[pp.first] > D[v] + pp.second){
	  D[pp.first] = D[v] + pp.second;
	  que.push(P(pp.first,D[pp.first]));
	}
      }
    }
}



int main(){

  while(true){
    cin >> n >> m;
    if(n+m == 0)break;
   
    for(int i=0;i<n+2;i++){
      matrix1[i].clear();
      matrix2[i].clear();
    }
    for(int i=0;i<n;i++){
      cin >> x >> y >> cost >> Time;
      matrix1[x].push_back(P(y,cost));
      matrix2[x].push_back(P(y,Time));
      matrix1[y].push_back(P(x,cost));
      matrix2[y].push_back(P(x,Time));
    }


   
   

    int k;
    cin >> k;
    for(int i=0;i<k;i++){
      cin >> p >> q >> r;
      if(r == 0){
	djkstra1(p);
	cout << D[q] << endl;
      }
      else{
	djkstra2(p);
	cout << D[q] << endl;
      }

    }

  }
  return 0;
}

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

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

const int INF = 10000000;
const int MAX_V = 100;
int d[2][MAX_V][MAX_V];

void solve() {
    while (true) {
        int E, V;
        cin >> E >> V;

        if (E == 0 && V == 0) break;

        //initialize
        REP(h, 2) {
            REP(i, V) {
                REP(j, V) {
                    if (i == j) d[h][i][j] = 0;
                    else        d[h][i][j] = INF;
                }
            }
        }

        //make graph
        REP(i, E) {
            int u, v, c1, c2;
            cin >> u >> v >> c1 >> c2;
            u--; v--;
            d[0][u][v] = c1; d[0][v][u] = c1;
            d[1][u][v] = c2; d[1][v][u] = c2;
        }

        //Warshall-Floyd
        REP(h, 2) {
            REP(k, V) {
                REP(i, V) {
                    REP(j, V) {
                        d[h][i][j] = min(d[h][i][j], d[h][i][k] + d[h][k][j]);
                    }
                }
            }
        }

        int K;
        cin >> K;

        REP(i, K) {
            int p, q, r;
            cin >> p >> q >> r;
            p--; q--;
            cout << d[r][p][q] << endl;
        }
    }
}


int main() {
    solve();
    return 0;
}

C++: #include <bits/stdc++.h>
#define r(i,n) for(int i=0;i<n;i++)
#define INF 1<<21
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[n][n]=a1[i][j]=INF;
    }
    while(m--){
      cin>>q>>w>>e>>r;q--;w--;
      a1[q][w]=a1[w][q]=e;
      a2[q][w]=a2[w][q]=r;
    }
    r(k,n)r(i,n)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--){
      cin>>q>>w>>r;q--;w--;
      if(r)cout<<a2[q][w]<<endl;
      else cout<<a1[q][w]<<endl;
    }
  }
}