add docs now

library/graphs/functional_graph_processor.hpp

@@ -1,4 +1,15 @@
 #pragma once
+//! https://github.com/Aeren1564/Algorithms/blob/master/Algorithm_Implementations_Cpp/Graph_Theory/Special_Graphs/functional_graph_processor.sublime-snippet
+//! @code
+//!   // 0 <= a[i] < n
+//!   auto [t, cycle] = func_graph(a);
+//!   if (auto id = t[v].cyc_pos)
+//!     assert(v == cycle[id->first][id->second]);
+//! @endcode
+//! t[v].root_of = first reachable node in a cycle
+//! t[v].childs = forest of reversed edges not in cycles
+//! @time O(n)
+//! @space O(n)
 struct func_graph {
   struct node {
     int root_of;

tests/library_checker_aizu_tests/handmade_tests/functional_graph.test.cpp

@@ -155,7 +155,7 @@ struct functional_graph_processor {
 int main() {
   cin.tie(0)->sync_with_stdio(0);
   for (int num_tests = 1000; num_tests--;) {
-    int n = rnd(1, 1000);
+    int n = rnd(1, 10000);
     vector<int> a(n);
     for (int i = 0; i < n; i++) a[i] = rnd(0, n - 1);
     auto [t, cycle] = func_graph(a);