1 files changed, 66 insertions, 0 deletions
diff --git a/2020/February/Gold/deleg.cpp b/2020/February/Gold/deleg.cpp
new file mode 100644
index 0000000..ee9144f
--- /dev/null
+++ b/2020/February/Gold/deleg.cpp
@@ -0,0 +1,66 @@
+#include <bits/stdc++.h>
+#define f first
+#define s second
+using namespace std;
+typedef pair<int, int> ii;
+
+int d[100001] = { 0 };
+vector<ii> G[100001];
+
+ii dfs(int u, int p) {
+	d[u] = d[p] + 1;
+	vector<ii> tmp;
+	for (auto& x : G[u]) {
+		if (!d[x.f] || d[x.f] > d[u]) tmp.push_back(x);
+	}
+	swap(G[u], tmp);
+	if (G[u].size() == 1) {
+		G[u][0] = dfs(G[u][0].f, u);
+		return ii(G[u][0].f, G[u][0].s + 1);
+	}
+	else if (!G[u].empty()) {
+		int tmp = 0;
+		for (auto& v : G[u]) v = dfs(v.f, u);
+	}
+	return ii(u, 1);
+}
+
+int solve(int u, int k) {
+	unordered_multiset<int> S;
+	for (auto& v : G[u]) {
+		int x = solve(v.f, k) + v.s;
+		if (x < 0) return -1e9;
+		if (x % k) S.insert(x % k);
+	}
+	int ret = 0;
+	while (!S.empty()) {
+		int x = *begin(S);
+		S.erase(S.find(x));
+		auto it = S.find(k - x);
+		if (it == end(S)) {
+			if (ret) return -1e9;
+			ret = x;
+		}
+		else S.erase(it);
+	}
+	return ret;
+}
+
+int main() {
+	ifstream cin("deleg.in");
+	ofstream cout("deleg.out");
+	ios_base::sync_with_stdio(0);
+	cin.tie(0), cout.tie(0);
+
+	int N; cin >> N;
+	for (int i = 1; i < N; ++i) {
+		int a, b; cin >> a >> b;
+		G[a].emplace_back(b, 1), G[b].emplace_back(a, 1);
+	}
+	int s = 1;
+	for (int u = 1; u <= N; ++u) {
+		if (G[u].size() > G[s].size()) s = u;
+	}
+	dfs(s, 0);
+	for (int i = 1; i < N; ++i) cout << ((N - 1) % i == 0 ? solve(s, i) == 0 : 0);
+}