Cod sursa(job #2697706)

Utilizator FrostfireMagirescu Tudor Frostfire Data 19 ianuarie 2021 13:23:08
Problema Flux maxim Scor 70
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.35 kb
#include <iostream>
#include <fstream>
#include <queue>
#define f first
#define s second
#define NMAX 1000
#define inf 2000000000

using namespace std;

ifstream fin("maxflow.in");
ofstream fout("maxflow.out");

int n, m, nod[NMAX+10][NMAX+10], p[NMAX+10], viz[NMAX+10], ans;
queue <int> Q;

int addFlow()
{	for(int i=1; i<=n; i++)
		p[i] = viz[i] = 0;
	while(!Q.empty())
		Q.pop();
	Q.push(1);
	viz[1] = 1;

	while(!Q.empty())
		{	int a = Q.front();
			Q.pop();
			for(int i=1; i<=n; i++)
				if(!viz[i] && nod[a][i])
					{	p[i] = a;
						viz[i] = 1;
						Q.push(i);
					}
		}
	return viz[n];
}

int main()
{	
	fin >> n >> m;
	for(int i=1; i<=m; i++)
		{	int nod1, nod2, c;
			fin >> nod1 >> nod2 >> c;
			nod[nod1][nod2] += c;
		}
	while(addFlow())
		{	for(int i=1; i<n; i++)
				{	if(viz[i] && nod[i][n])
						{	int newFlow = nod[i][n], curr = i;
							while(curr != 1)
								{	int pr = p[curr];
									newFlow = min(newFlow, nod[pr][curr]);
									curr = pr;
								}
							if(!newFlow) continue;
							nod[i][n] -= newFlow;
							nod[n][i] += newFlow;
							curr = i;
							while(curr != 1)
								{	int pr = p[curr];
									nod[pr][curr] -= newFlow;
									nod[curr][pr] += newFlow;
									curr = pr;
								}
							ans += newFlow;
						}
				}
		}
	fout << ans << '\n';
	return 0;
}