Revert "trying some optimizations"

This reverts commit 5540481.

Author: lrvideckis

library/graphs/strongly_connected_components/offline_incremental_scc.hpp

@@ -16,35 +16,37 @@ vi offline_incremental_scc(vector<array<int, 2>> eds,
   vi ids(n, -1), joins(m, m), idx(m), vs(n), scc_id;
   iota(all(idx), 0);
   vector<vi> adj;
-  auto divide_and_conquer = [&](auto&& self, int el,
-                                int er, int tl, int tr) {
+  auto divide_and_conquer = [&](auto&& self, auto el,
+                                auto er, int tl, int tr) {
     adj.clear();
     int mid = midpoint(tl, tr);
-    rep(i, el, er) {
-      auto& [u, v] = eds[idx[i]];
-      for (int w : {u, v})
-        if (ids[w] == -1) {
-          ids[w] = sz(adj);
-          vs[sz(adj)] = w;
-          adj.emplace_back();
-        }
+    for (auto it = el; it != er; it++) {
+      auto& [u, v] = eds[*it];
+      for (int w : {u, v}) {
+        if (ids[w] != -1) continue;
+        ids[w] = sz(adj);
+        vs[sz(adj)] = w;
+        adj.emplace_back();
+      }
       u = ids[u], v = ids[v];
-      if (idx[i] <= mid) adj[u].push_back(v);
+      if (*it <= mid) adj[u].push_back(v);
     }
     rep(i, 0, sz(adj)) ids[vs[i]] = -1;
     scc_id = sccs(adj).scc_id;
-    int split = partition(begin(idx) + el, begin(idx) + er, [&](int i) { return scc_id[eds[i][0]] == scc_id[eds[i][1]]; }) - begin(idx);
-    rep(i, el, split) joins[idx[i]] = mid;
+    auto split = partition(el, er, [&](int i) {
+      return scc_id[eds[i][0]] == scc_id[eds[i][1]];
+    });
+    for (auto it = el; it != split; it++) joins[*it] = mid;
     if (tr - tl == 1) return;
-    rep(i, split, er) {
-      auto& [u, v] = eds[idx[i]];
+    for (auto it = split; it != er; it++) {
+      auto& [u, v] = eds[*it];
       u = scc_id[u], v = scc_id[v];
     }
     self(self, el, split, tl, mid);
     self(self, split, er, mid, tr);
   };
   // uses -1 as the lower bound to correctly handle
   // self-edges
-  divide_and_conquer(divide_and_conquer, 0, m, -1, m);
+  divide_and_conquer(divide_and_conquer, all(idx), -1, m);
   return joins;
 }

tests/library_checker_aizu_tests/graphs/offline_incremental_scc.test.cpp

@@ -13,6 +13,7 @@ int main() {
   vector<array<int, 2>> eds(m);
   for (auto& [u, v] : eds) cin >> u >> v;
   auto joins = offline_incremental_scc(eds, n);
+  // assert joins[i] == -1 for self-edges
   for (int t = 0; t < m; t++)
     assert((eds[t][0] == eds[t][1]) == (joins[t] == -1));
   vector<int> order(m);

tests/library_checker_aizu_tests/math/xor_basis_intersection.test.cpp

@@ -17,11 +17,10 @@ int main() {
   cin.tie(0)->sync_with_stdio(0);
   int t;
   cin >> t;
-  basis<int> basis1, basis2;
   while (t--) {
     int n;
     cin >> n;
-    basis1.b.clear();
+    basis<int> basis1;
     for (int i = 0; i < n; i++) {
       int val;
       cin >> val;
@@ -30,7 +29,7 @@ int main() {
     check_condition(basis1);
     int m;
     cin >> m;
-    basis2.b.clear();
+    basis<int> basis2;
     for (int j = 0; j < m; j++) {
       int val;
       cin >> val;