Problem: Examples

Input

4 5 2
0 1 2 1
0 2 1 2
1 2 1 1
1 3 1 3
2 3 2 1


Output

6


Input




Output

Solution (in CPP):

Solution:
#include <vector>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <stack>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <bitset>
#include <complex>
using namespace std;
#define REP(i,n) for(int i = 0; i < (int)n; i++)
#define FOR(i,a,b) for(int i = a; i < (int)b; i++)
#define pb push_back
#define mp make_pair
typedef vector<int> vi;
typedef pair<int, int> pi;
typedef long long ll;
typedef unsigned long long ull;
const int dx[] = {1, 0, -1, 0}, dy[] = {0, 1, 0, -1};
const int INF = 1 << 27;
const int MAX_V = 101;
//////////////////////////////
// ????°??????¨???
struct edge { int to, cap, cost, rev; };

int V;
vector<edge> G[MAX_V]; //??°???????????£??\???????????¨???
int h[MAX_V]; //??????????????£???
int dist[MAX_V]; //???????????¢
int prevv[MAX_V], preve[MAX_V]; // ??´??????????????¨???

void add_edge(int from, int to, int cap, int cost){
  G[from].push_back((edge){to, cap, cost, (int)G[to].size()});
  G[to].push_back((edge){from, 0, -cost, (int)(G[from].size()) - 1});
}
// s??????t????????????f???????°??????¨???
// ??????????????´??????-1?????????
int min_cost_flow(int s, int t, int f){
  int res = 0;
  fill(h, h + V, 0);
  while(f > 0){
    priority_queue<pi, vector<pi>, greater<pi> > que;
    fill(dist, dist + V, INF);
    dist[s] = 0;
    que.push(pi(0, s));
    while(!que.empty()){
      pi p = que.top(); que.pop();
      int v = p.second;
      if(dist[v] < p.first) continue;
      REP(i, G[v].size()){
        edge &e = G[v][i];
        if(e.cap > 0 && dist[e.to] > dist[v] + e.cost + h[v] - h[e.to]){
          dist[e.to] = dist[v] + e.cost + h[v] - h[e.to];
          prevv[e.to] = v;
          preve[e.to] = i;
          que.push(pi(dist[e.to], e.to));
        }
      }
    }
    if(dist[t] == INF) return -1;
    REP(v, V) h[v] += dist[v];
    int d = f;
    for(int v = t; v != s; v = prevv[v]) d = min(d, G[prevv[v]][preve[v]].cap);
    f -= d;
    res += d * h[t];
    for(int v = t; v != s; v = prevv[v]){
      edge &e = G[prevv[v]][preve[v]];
      e.cap -= d;
      G[v][e.rev].cap += d;
    }
  }
  return res;
}

int main() {
  int E, F; cin >>V >>E >>F;
  REP(i, E){
    int a,b,c,d; cin >> a >> b >> c >> d;
		add_edge(a,b,c,d);
  }
  cout << min_cost_flow(0, V-1, F)  <<endl;
  return 0;
}