Linear rmq golf idea (#218)

* golf

* fix

* revert

Author: lrvideckis

library/data_structures_[l,r]/linear_rmq.hpp

@@ -19,17 +19,16 @@ template<class T, class F> struct linear_rmq {
   vi in, asc, head;
   linear_rmq(const vector<T>& a, F cmp):
     n(sz(a)), a(a), cmp(cmp), in(n), asc(n), head(n + 1) {
-    vi st{-1};
+    vi st(n + 1, -1);
+    int t = 0;
     rep(i, 0, n + 1) {
       int prev = 0;
-      while (sz(st) > 1 &&
-             (i == n || !cmp(a[st.back()], a[i]))) {
-        head[prev] = st.back();
-        auto j = end(st)[-2] + 1u, k = bit_floor(i ^ j);
-        in[st.back()] = prev = i & -k, asc[j] |= k;
-        st.pop_back();
+      while (t && (i == n || !cmp(a[st[t]], a[i]))) {
+        head[prev] = st[t];
+        auto j = st[t - 1] + 1u, k = bit_floor(i ^ j);
+        in[st[t--]] = prev = i & -k, asc[j] |= k;
       }
-      st.push_back(head[prev] = i);
+      st[++t] = head[prev] = i;
     }
     rep(i, 1, n)
       asc[i] = (asc[i] | asc[i - 1]) & -(in[i] & -in[i]);

tests/.config/.cppcheck_suppression_list

@@ -53,7 +53,6 @@ constVariableReference:library_checker_aizu_tests/handmade_tests/dsu_size.test.c
 constVariableReference:../library/trees/centroid_decomp_uncommon/count_paths_per_length.hpp:34
 constVariablePointer:../kactl/content/numerical/FastFourierTransform.h:39
 cstyleCast:../kactl/content/numerical/FastFourierTransform.h:39
-derefInvalidIterator:../library/data_structures_[l,r]/linear_rmq.hpp:28
 derefInvalidIterator:library_checker_aizu_tests/handmade_tests/n_choose_k.test.cpp:13
 unreadVariable:library_checker_aizu_tests/handmade_tests/permutation_tree_small.test.cpp:12
 uninitvar:library_checker_aizu_tests/handmade_tests/seg_tree_find_small.test.cpp:41