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>

#define _overload(_1,_2,_3,name,...) name
#define _rep(i,n) _range(i,0,n)
#define _range(i,a,b) for(int i=int(a);i<int(b);++i)
#define rep(...) _overload(__VA_ARGS__,_range,_rep,)(__VA_ARGS__)

#define _rrep(i,n) _rrange(i,n,0)
#define _rrange(i,a,b) for(int i=int(a)-1;i>=int(b);--i)
#define rrep(...) _overload(__VA_ARGS__,_rrange,_rrep,)(__VA_ARGS__)

#define _all(arg) begin(arg),end(arg)
#define uniq(arg) sort(_all(arg)),(arg).erase(unique(_all(arg)),end(arg))
#define getidx(ary,key) lower_bound(_all(ary),key)-begin(ary)
#define clr(a,b) memset((a),(b),sizeof(a))
#define bit(n) (1LL<<(n))
#define popcount(n) (__builtin_popcountll(n))

template<class T>bool chmax(T &a, const T &b) { return (a<b)?(a=b,1):0;}
template<class T>bool chmin(T &a, const T &b) { return (b<a)?(a=b,1):0;}

using namespace std;

const int dx[8]={1,0,-1,0,1,-1,-1,1};
const int dy[8]={0,1,0,-1,1,1,-1,-1};

using edge=struct {int to,cap,cost,rev;};
using G=vector<vector<edge>>;
const int inf=1<<29;

void add_edge(G &graph,int a,int b,int c,int d){
	graph[a].push_back({b,c,d,int(graph[b].size())});
	graph[b].push_back({a,0,-d,int(graph[a].size()-1)});
}

int min_cost_flow(G &graph,int s,int t,int f){
	int res=0;
	while(f){
		int n=graph.size(),update;
		vector<int> dist(n,inf),pv(n,0),pe(n,0);
		dist[s]=0;

		rep(loop,n){
			update=false;
			rep(v,n)rep(i,graph[v].size()){
				edge &e=graph[v][i];
				if(e.cap>0 && chmin(dist[e.to],dist[v]+e.cost)){
					pv[e.to]=v,pe[e.to]=i;
					update=true;
				}
			}
			if(!update) break;
		}

		if(dist[t]==inf) return -1;

		int d=f;
		for(int v=t;v!=s;v=pv[v]) chmin(d,graph[pv[v]][pe[v]].cap);
		f-=d,res+=d*dist[t];

		for(int v=t;v!=s;v=pv[v]){
			edge &e=graph[pv[v]][pe[v]];
			e.cap-=d;
			graph[v][e.rev].cap+=d;
		}
	}
	return res;
}

int main(void){
	int n,m,f;
	cin >> n >> m >> f;
	G graph(n);
	rep(i,m){
		int a,b,c,d;
		cin >> a >> b >> c >> d;
		add_edge(graph,a,b,c,d);
	}
	cout << min_cost_flow(graph,0,n-1,f) << endl;
	return 0;
}