mzuenni tests

1 files changed, 64 insertions, 0 deletions

diff --git a/content/graph/pushRelabel.cpp b/content/graph/pushRelabel.cpp
new file mode 100644
index 0000000..73a9eae
--- /dev/null
+++ b/content/graph/pushRelabel.cpp
@@ -0,0 +1,64 @@
+struct Edge {
+	int to, rev;
+	ll f, c;
+};
+
+vector<vector<Edge>> adj;
+vector<vector<int>> hs;
+vector<ll> ec;
+vector<int> cur, H;
+
+void addEdge(int u, int v, ll c) {
+	adj[u].push_back({v, (int)sz(adj[v]), 0, c});
+	adj[v].push_back({u, (int)sz(adj[u])-1, 0, 0});
+}
+
+void addFlow(Edge& e, ll f) {
+	if (ec[e.to] == 0 && f > 0)
+		hs[H[e.to]].push_back(e.to);
+	e.f += f;
+	adj[e.to][e.rev].f -= f;
+	ec[e.to] += f;
+	ec[adj[e.to][e.rev].to] -= f;
+}
+
+ll maxFlow(int s, int t) {
+	int n = sz(adj);
+	hs.assign(2*n, {});
+	ec.assign(n, 0);
+	cur.assign(n, 0);
+	H.assign(n, 0);
+	H[s] = n;
+	ec[t] = 1;//never set t to active...
+	vector<int> co(2*n);
+	co[0] = n - 1;
+	for (Edge& e : adj[s]) addFlow(e, e.c);
+	for (int hi = 0;;) {
+		while (hs[hi].empty()) if (!hi--) return -ec[s];
+		int v = hs[hi].back();
+		hs[hi].pop_back();
+		while (ec[v] > 0) {
+			if (cur[v] == sz(adj[v])) {
+				H[v] = 2*n;
+				for (int i = 0; i < sz(adj[v]); i++) {
+					Edge& e = adj[v][i];
+					if (e.c - e.f > 0 &&
+					    H[v] > H[e.to] + 1) {
+						H[v] = H[e.to] + 1;
+						cur[v] = i;
+				}}
+				co[H[v]]++;
+				if (!--co[hi] && hi < n) {
+					for (int i = 0; i < n; i++) {
+						if (hi < H[i] && H[i] < n) {
+							co[H[i]]--;
+							H[i] = n + 1;
+				}}}
+				hi = H[v];
+			} else {
+				Edge& e = adj[v][cur[v]];
+				if (e.c - e.f > 0 && H[v] == H[e.to] + 1) {
+					addFlow(adj[v][cur[v]], min(ec[v], e.c - e.f));
+				} else {
+					cur[v]++;
+}}}}}