different style + nits

Author: lrvideckis

library/data_structures/uncommon/linear_rmq.hpp

@@ -1,49 +1,49 @@
 #pragma once
 //! https://codeforces.com/blog/entry/125371?#comment-1173604
 //! @code
-//!   linear_rmq rmq1(a, less());//right-most min
-//!   linear_rmq rmq2(a, less_equal());//left-most min
-//!   linear_rmq rmq3(a, greater());//right-most max
-//!   linear_rmq rmq4(a, greater_equal());//left-most max
+//!   linear_rmq rmq1(a, less());          //right-most min
+//!   linear_rmq rmq2(a, less_equal());    //left-most min
+//!   linear_rmq rmq3(a, greater());       //right-most max
+//!   linear_rmq rmq4(a, greater_equal()); //left-most max
 //!   linear_rmq rmq5(a, [&](auto& x, auto& y) {
 //!     return x < y;
 //!   });
 //! @endcode
 //! @time O(n + q)
 //! @space O(n)
 template<class T, class F> struct linear_rmq {
+  int n;
   vector<T> a;
   F cmp;
-  vi head;
-  vector<array<int, 2>> t;
+  vi asc, in, head;
   linear_rmq(const vector<T>& a, F cmp):
-    a(a), cmp(cmp), head(sz(a) + 1), t(sz(a)) {
+    n(sz(a)), a(a), cmp(cmp), asc(n), in(n), head(n + 1) {
     vi st{-1};
-    for (int i = 0; i <= sz(a); i++) {
+    rep(i, 0, n + 1) {
       int prev = -1;
       while (st.back() != -1 &&
-        (i == sz(a) || !cmp(a[st.back()], a[i]))) {
+        (i == n || !cmp(a[st.back()], a[i]))) {
         if (prev != -1) head[prev] = st.back();
-        int pw2 = 1 << __lg((end(st)[-2] + 1) ^ i);
-        t[st.back()][0] = prev = i & -pw2;
+        int pw2 = bit_floor((end(st)[-2] + 1u) ^ i);
+        in[st.back()] = prev = i & -pw2;
         st.pop_back();
-        t[st.back() + 1][1] |= pw2;
+        asc[st.back() + 1] |= pw2;
       }
       if (prev != -1) head[prev] = i;
       st.push_back(i);
     }
-    rep(i, 1, sz(a)) t[i][1] =
-      (t[i][1] | t[i - 1][1]) & -(t[i][0] & -t[i][0]);
+    rep(i, 1, n) asc[i] =
+      (asc[i] | asc[i - 1]) & -(in[i] & -in[i]);
   }
-  int query_idx(int l, int r) { // [l, r]
-    if (unsigned j = t[l][0] ^ t[r][0]; j) {
-      j = t[l][1] & t[r][1] & -bit_floor(j);
-      if (unsigned k = t[l][1] ^ j; k)
-        k = bit_floor(k), l = head[(t[l][0] & -k) | k];
-      if (unsigned k = t[r][1] ^ j; k)
-        k = bit_floor(k), r = head[(t[r][0] & -k) | k];
+  int idx(int l, int r) { // [l, r]
+    if (unsigned j = in[l] ^ in[r]; j) {
+      j = asc[l] & asc[r] & -bit_floor(j);
+      if (unsigned k = asc[l] ^ j; k)
+        k = bit_floor(k), l = head[(in[l] & -k) | k];
+      if (unsigned k = asc[r] ^ j; k)
+        k = bit_floor(k), r = head[(in[r] & -k) | k];
     }
     return cmp(a[l], a[r]) ? l : r;
   }
-  T query(int l, int r) { return a[query_idx(l, r)]; }
+  T query(int l, int r) { return a[idx(l, r)]; }
 };

tests/library_checker_aizu_tests/data_structures/rmq_linear.test.cpp

@@ -16,21 +16,21 @@ int main() {
   while (q--) {
     int l, r;
     cin >> l >> r;
-    int idx_right_min = rmq_less.query_idx(l, r - 1);
+    int idx_right_min = rmq_less.idx(l, r - 1);
     assert(idx_right_min + 1 == r ||
       rmq_less.query(idx_right_min + 1, r - 1) >
         a[idx_right_min]);
     assert(l <= idx_right_min && idx_right_min < r);
     assert(rmq_less.query(l, r - 1) == a[idx_right_min]);
     assert(
-      idx_right_min == rmq_greater.query_idx(l, r - 1));
-    int idx_left_min = rmq_less_equal.query_idx(l, r - 1);
+      idx_right_min == rmq_greater.idx(l, r - 1));
+    int idx_left_min = rmq_less_equal.idx(l, r - 1);
     assert(l == idx_left_min ||
       rmq_less_equal.query(l, idx_left_min - 1) >
         a[idx_left_min]);
     assert(l <= idx_left_min && idx_left_min < r);
     assert(idx_left_min ==
-      rmq_greater_equal.query_idx(l, r - 1));
+      rmq_greater_equal.idx(l, r - 1));
     assert(a[idx_right_min] == a[idx_left_min]);
     assert(idx_left_min <= idx_right_min);
     cout << a[idx_right_min] << '\n';