Cod sursa(job #2396154)

Utilizator vic2002Melinceanu Victor vic2002 Data 3 aprilie 2019 11:35:42
Problema Flux maxim Scor 60
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.31 kb
#pragma GCC optimize("O3")
#include<bits/stdc++.h>
#define rc(x) return cout<<x<<endl,0
#define pb push_back
#define in insert
#define er erase
#define fd find
#define fr first
#define sc second
typedef long long ll;
typedef long double ld;
const ll INF=0x3f3f3f3f3f3f3f3f;
const ll llinf=(1LL<<62);
const int inf=(1<<30);
const int nmax=1e3+50;
const int mod=1e9+7;
using namespace std;
ll x,y,flow,nw,pr[nmax],cp[nmax][nmax],n,i,m,z;
vector<ll>a[nmax];
ll bfs()
{
	ll i,x,y,fl,f;
	for(i=1;i<=n;i++)pr[i]=-1;
	pr[1]=-2;
	queue<pair<ll,ll> >q;
	q.push({1,llinf});
	while(!q.empty())
	{
		fl=q.front().sc;
		x=q.front().fr;
		q.pop();
		for(i=0;i<a[x].size();i++)
		{
			y=a[x][i];
			if(pr[y]==-1 && cp[x][y])
			{
				f=min(fl,cp[x][y]);
				pr[y]=x;
				if(y==n)return f;
				q.push({y,f});
			}
		}
	}
	return 0;
}
int main()
{
	freopen("maxflow.in","r",stdin);
	freopen("maxflow.out","w",stdout);
	//mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
	ios_base::sync_with_stdio(false);cin.tie(0);cerr.tie(0);cout.tie(0);
	cin>>n>>m;
	while(m--)
	{
		cin>>x>>y>>z;
		a[x].pb(y);
		cp[x][y]=z;
	}
	while(nw=bfs())
	{
		flow+=nw;
		x=n;
		while(x!=1)
		{
			cp[pr[x]][x]-=nw;
			cp[x][pr[x]]+=nw;
			x=pr[x];
		}
	}
	cout<<flow<<endl;
    return 0;
}