improvde tests

1 files changed, 67 insertions, 0 deletions

diff --git a/graph/test/util.cpp b/graph/test/util.cpp
new file mode 100644
index 0000000..8bec1ee
--- /dev/null
+++ b/graph/test/util.cpp
@@ -0,0 +1,67 @@
+
+namespace util {
+
+mt19937 rd(0);
+
+int randint(int x) {
+	assert(x > 0);
+	return uniform_int_distribution<int>(0, x-1)(rd);
+}
+
+void shuffle_adj_lists(vector<vector<int>> &adj) {
+	for (auto &a: adj) ranges::shuffle(a, rd);
+}
+
+vector<vector<int>> random_tree(int n) {
+	vector<vector<int>> adj(n);
+
+	vector<vector<int>> components(n);
+	for (int i = 0; i < n; i++) components[i].push_back(i);
+	while (components.size() > 1) {
+		int c1 = randint(components.size());
+		int c2 = randint(components.size()-1);
+		c2 += (c2 >= c1);
+
+		int v1 = components[c1][randint(components[c1].size())];
+		int v2 = components[c2][randint(components[c2].size())];
+
+		adj[v1].push_back(v2);
+		adj[v2].push_back(v1);
+
+		if (components[c1].size() < components[c2].size()) swap(c1, c2);
+		for (int v: components[c2]) components[c1].push_back(v);
+		swap(components[c2], components.back());
+		components.pop_back();
+	}
+
+	shuffle_adj_lists(adj);
+	return adj;
+}
+
+vector<vector<int>> path(int n) {
+	vector<vector<int>> adj(n);
+	for (int i = 1; i < n; i++) {
+		adj[i-1].push_back(i);
+		adj[i].push_back(i-1);
+	}
+	return adj;
+}
+
+template<typename... Ts>
+void shuffle_graph(vector<vector<int>> &adj, Ts &...vertex) {
+	int n = adj.size();
+	vector<int> perm(n);
+	iota(perm.begin(), perm.end(), 0);
+	ranges::shuffle(perm, rd);
+
+	vector<vector<int>> new_adj(n);
+	for (int i = 0; i < n; i++) {
+		auto &a = new_adj[perm[i]] = move(adj[i]);
+		for (int &v: a) v = perm[v];
+	}
+	adj = move(new_adj);
+	shuffle_adj_lists(adj);
+	((vertex = perm[vertex]), ...);
+}
+
+}