1 files changed, 109 insertions, 0 deletions
diff --git a/graph/pushRelabel2.cpp b/graph/pushRelabel2.cpp
new file mode 100644
index 0000000..8b5f0c6
--- /dev/null
+++ b/graph/pushRelabel2.cpp
@@ -0,0 +1,109 @@
+constexpr ll inf = 1ll<<60;
+
+struct edge {
+	int from, to; 
+	ll f, c;
+};
+
+vector<edge> edges;
+vector<vector<int>> adjlist, llist;
+vector<int> height, ccount, que;
+vector<ll> excess;
+vector<list<int>> dlist;
+vector<list<int>::iterator> iter;
+int highest, highestActive;
+
+void addEdge(int from, int to, ll c) {
+	adjlist[from].push_back(edges.size());
+	edges.push_back({from, to, 0, c});
+	adjlist[to].push_back(edges.size());
+	edges.push_back({to, from, 0, 0});
+}
+
+void globalRelabel(int n, int t) {
+	height.assign(n, n);
+	height[t] = 0;
+	ccount.assign(n, 0);
+	que.assign(n+1, 0);
+	int qh = 0, qt = 0;
+	for (que[qt++] = t; qh < qt;) {
+		int u = que[qh++], h = height[u] + 1;
+		for (int id : adjlist[u]) {
+			if (height[edges[id].to] == n && edges[id ^ 1].c - edges[id ^ 1].f > 0) {
+				ccount[height[edges[id].to] = h]++;
+				que[qt++] = edges[id].to;
+	}}}
+	llist.assign(n+1, {});
+	dlist.assign(n+1, {});
+	for (int u = 0; u < n; u++) {
+		if (height[u] < n) {
+			iter[u] = dlist[height[u]].insert(dlist[height[u]].begin(), u);
+			if (excess[u] > 0) llist[height[u]].push_back(u);
+	}}
+	highest = highestActive = height[que[qt - 1]];
+}
+
+void push(int u, int id) {
+	int v = edges[id].to;
+	ll df = min(excess[u], edges[id].c - edges[id].f);
+	edges[id].f += df;
+	edges[id^1].f -= df;
+	excess[u] -= df;
+	excess[v] += df;
+	if (0 < excess[v] && excess[v] <= df) llist[height[v]].push_back(v);
+}
+
+void discharge(int n, int u) {
+	int nh = n;
+	for (int id : adjlist[u]) {
+		if (edges[id].c - edges[id].f > 0) {
+			if (height[u] == height[edges[id].to] + 1) {
+				push(u, id);
+				if (!excess[u]) return;
+			} else {
+				nh = min(nh, height[edges[id].to] + 1);
+	}}}
+	int h = height[u];
+	if (ccount[h] == 1) {
+		for (int i = h; i <= highest; i++) {
+			for (auto p : dlist[i]) --ccount[height[p]], height[p] = n;
+			dlist[i].clear();
+		}
+		highest = h - 1;
+	} else {
+		--ccount[h], iter[u] = dlist[h].erase(iter[u]), height[u] = nh;
+		if (nh == n) return;
+		++ccount[nh], iter[u] = dlist[nh].insert(dlist[nh].begin(), u);
+		highest = max(highest, highestActive = nh);
+		llist[nh].push_back(u);
+}}
+
+ll maxFlow(int s, int t) {
+	int n = adjlist.size();
+	llist.assign(n + 1, {});
+	dlist.assign(n + 1, {});
+	highestActive = highest = 0;
+	height.assign(n, 0);
+	height[s] = n;
+	iter.resize(n);
+	for (int i = 0; i < n; i++) {
+		if (i != s) iter[i] = dlist[height[i]].insert(dlist[height[i]].begin(), i);
+	}
+	ccount.assign(n, 0);
+	ccount[0] = n-1;
+	excess.assign(n, 0);
+	excess[s] = inf;
+	excess[t] = -inf;
+	for (int id : adjlist[s]) push(s, id);
+	globalRelabel(n, t);
+	while (highestActive >= 0) {
+		if (llist[highestActive].empty()) {
+			highestActive--;
+			continue;
+		}
+		int u = llist[highestActive].back();
+		llist[highestActive].pop_back();
+		discharge(n, u);
+	}
+	return excess[t] + inf;
+}
+\ No newline at end of file