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 <bits/stdc++.h>
using namespace std;
#define rep(i,j,k) for(int i = (int)j;i <= (int)k;i ++)
#define debug(x) cerr<<#x<<":"<<x<<endl

typedef long long int ll;
typedef unsigned long long int ull;
#define BIG_NUM 2000000000
#define MOD 1000000007
#define EPS 0.000000001
using namespace std;


#define NUM 100


struct Edge{
	Edge(int arg_to,int arg_capacity,int arg_cost,int arg_rev_index){
		to = arg_to;
		capacity = arg_capacity;
		cost = arg_cost;
		rev_index = arg_rev_index;
	}

	int to,capacity,cost,rev_index;
};

int V;
vector<Edge> G[NUM];
int dist[NUM];
int pre_node[NUM],pre_edge[NUM];


void add_edge(int from,int to,int capacity,int cost){
	G[from].push_back(Edge(to,capacity,cost,G[to].size()));
	G[to].push_back(Edge(from,0,-cost,G[from].size()-1));
}

int min_cost_flow(int source,int sink,int flow){
	int ret = 0;
	while(flow > 0){

		for(int i = 0; i < V; i++)dist[i] = BIG_NUM;
		dist[source] = 0;
		bool update = true;
		while(update){
			update = false;
			for(int node_id = 0; node_id < V; node_id++){
				if(dist[node_id] == BIG_NUM)continue;
				for(int i = 0; i < G[node_id].size(); i++){
					Edge &e = G[node_id][i];
					if(e.capacity > 0 && dist[e.to] > dist[node_id]+e.cost){
						dist[e.to] = dist[node_id]+e.cost;
						pre_node[e.to] = node_id;
						pre_edge[e.to] = i;
						update = true;
					}
				}
			}
		}

		if(dist[sink] == BIG_NUM){
			return -1;
		}

		int tmp_flow = flow;
		for(int node_id = sink; node_id != source; node_id = pre_node[node_id]){
			tmp_flow = min(tmp_flow,G[pre_node[node_id]][pre_edge[node_id]].capacity);
		}
		flow -= tmp_flow;
		ret += tmp_flow*dist[sink];
		for(int node_id = sink; node_id != source; node_id = pre_node[node_id]){
			Edge &e = G[pre_node[node_id]][pre_edge[node_id]];
			e.capacity -= tmp_flow;
			G[node_id][e.rev_index].capacity += tmp_flow;
		}
	}
	return ret;
}

int main(){

	int E,F;
	scanf("%d %d %d",&V,&E,&F);

	int from,to,capacity,cost;
	for(int loop = 0; loop < E; loop++){
		scanf("%d %d %d %d",&from,&to,&capacity,&cost);
		add_edge(from,to,capacity,cost);
	}

	printf("%d\n", min_cost_flow(0,V-1,F));

	return 0;
}