Pagini recente » Cod sursa (job #3136806) | Cod sursa (job #1111279) | Cod sursa (job #2459543) | Cod sursa (job #481844) | Cod sursa (job #1736876)
#include <bits/stdc++.h>
using namespace std;
constexpr int MAX_N = 1000 + 1;
constexpr int MAX_M = 5000 + 1;
constexpr int NIL = -1;
struct Edge
{
int flow;
int capacity;
int nod;
int urm;
};
Edge G[2 * MAX_M];
int head[MAX_N];
int tata[MAX_N];
int pointer[MAX_N];
int N, M;
int contor;
void addEdge(int x, int y, int c)
{
G[contor] = {0, c, y, head[x]};
head[x] = contor++;
}
bool bfs(int S, int T)
{
for (int i = 1; i <= N; ++i)
{
tata[i] = 0;
pointer[i] = 0;
}
queue<int> Q;
tata[S] = S;
Q.push(S);
while (!Q.empty())
{
int node = Q.front();
Q.pop();
for (int p = head[node]; p != NIL; p = G[p].urm)
{
int son = G[p].nod;
if (!tata[son] && G[p].capacity > G[p].flow)
{
pointer[son] = p;
tata[son] = node;
if (son == T)
return true;
Q.push(son);
}
}
}
return false;
}
int maxFlow(int S, int T)
{
int totalFlow = 0;
while (bfs(S, T))
{
for (int p = head[T]; p != NIL; p = G[p].urm)
{
int son = G[p].nod;
if (tata[son] != 0 && G[p ^ 1].capacity > G[p ^ 1].flow)
{
pointer[T] = p ^ 1;
tata[T] = son;
int minFlow = numeric_limits<int>::max() / 2;
int node = T;
while (node != S)
{
minFlow = min(minFlow, G[ pointer[node] ].capacity - G[ pointer[node] ].flow);
node = tata[node];
}
totalFlow += minFlow;
node = T;
while (node != S)
{
G[ pointer[node] ].flow += minFlow;
G[ pointer[node] ^ 1 ].flow -= minFlow;
node = tata[node];
}
}
}
}
return totalFlow;
}
int main()
{
ifstream in("maxflow.in");
ofstream out("maxflow.out");
in >> N >> M;
for (int i = 1; i <= N; ++i)
head[i] = NIL;
for (int i = 1; i <= M; ++i)
{
int a, b, c;
in >> a >> b >> c;
addEdge(a, b, c);
addEdge(b, a, 0);
}
out << maxFlow(1, N) << endl;
return 0;
}