1 files changed, 59 insertions, 0 deletions
diff --git a/15/dec/plat/maxflow.cpp b/15/dec/plat/maxflow.cpp
new file mode 100644
index 0000000..88f3cda
--- /dev/null
+++ b/15/dec/plat/maxflow.cpp
@@ -0,0 +1,59 @@
+#include <algorithm>
+#include <fstream>
+#include <vector>
+#include <cmath>
+using namespace std;
+
+int N, ans = 0, pre[50005], d[50005] = { 0 }, L[20][50005] = { 0 };
+vector<int> G[50005];
+
+void dfs(int u, int p) {
+	d[u] = d[p] + 1;
+	L[0][u] = p;
+	for (int i = 0; (1 << i) < N; i++) if (L[i][u]) L[i + 1][u] = L[i][L[i][u]];
+	for (int v : G[u]) if (v != p) dfs(v, u);
+}
+
+int lca(int u, int v) {
+	if (d[u] > d[v]) swap(u, v);
+	for (int i = log2(N); i >= 0; i--) if (d[v] - (1 << i) >= d[u]) v = L[i][v];
+	if (u == v) return u;
+	for (int i = log2(N); i >= 0; i--) if (L[i][u] && L[i][u] != L[i][v]) u = L[i][u], v = L[i][v];
+	return L[0][u];
+}
+
+void solve(int u, int p) {
+	for (int v : G[u]) {
+		if (v != p) {
+			solve(v, u);
+			pre[u] += pre[v];
+		}
+	}
+	ans = max(pre[u], ans);
+}
+
+int main() {
+	ifstream cin("maxflow.in");
+	ofstream cout("maxflow.out");
+
+	int K;
+	cin >> N >> K;
+	for (int i = 0; i < N - 1; i++) {
+		int x, y;
+		cin >> x >> y;
+		G[x].push_back(y);
+		G[y].push_back(x);
+	}
+
+	dfs(1, 0);
+
+	while (K--) {
+		int s, t;
+		cin >> s >> t;
+		pre[s]++, pre[t]++;
+		pre[L[0][lca(s, t)]]--, pre[lca(s, t)]--;
+	}
+
+	solve(1, 0);
+	cout << ans << endl;
+}