Cod sursa(job #2396200)

Utilizator vic2002Melinceanu Victor vic2002 Data 3 aprilie 2019 11:58:11
Problema Flux maxim Scor 10
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.45 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;
int x,y,flow,nw,pr[nmax],cp[nmax][nmax],n,i,m,z,v[nmax];
vector<int>a[nmax];
bool bfs()
{
	int i,x,y;
	for(i=1;i<=n;i++)v[i]=0;
	v[1]=1;
	queue<int>q;
	q.push(1);
	while(!q.empty())
	{
		x=q.front();
		q.pop();
		for(i=0;i<a[x].size();i++)
		{
			y=a[x][i];
			if(!v[y] && cp[x][y])
			{
				pr[y]=x;
				v[y]=1;
				q.push(y);
			}
		}
	}
	return v[n];
}
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);
		a[y].pb(x);
		cp[x][y]=z;
	}
	while(bfs())
	{
		for(i=0;i<a[n].size();i++)
		{
			y=a[n][i];
			if(!cp[y][n] || !v[y])continue;
			nw=1e9;
			pr[n]=y;
			x=n;
			while(x!=1)
			{
				nw=min(nw,cp[pr[x]][x]);
				x=pr[x];
			}
			x=n;
			while(x!=1)
			{
				cp[pr[x]][x]-=nw;
				cp[x][pr[x]]+=nw;
				x=pr[x];
			}
			flow+=nw;
		}
	}
	cout<<flow<<'\n';
    return 0;
}