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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(sz(edges));
edges.push_back({from, to, 0, c});
adjlist[to].push_back(sz(edges));
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 = sz(adjlist);
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;
}
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