refactor

Author: lrvideckis

library/data_structures_[l,r)/seg_tree.hpp

@@ -31,5 +31,5 @@ template<class T, class F> struct tree {
     }
     return op(x, y);
   }
-#include "seg_tree_uncommon/walk.hpp"
+#include "seg_tree_uncommon/max_right.hpp"
 };

…uctures_[l,r)/seg_tree_uncommon/walk.hpp …es_[l,r)/seg_tree_uncommon/max_right.hpplibrary/data_structures_[l,r)/seg_tree_uncommon/walk.hpp renamed to library/data_structures_[l,r)/seg_tree_uncommon/max_right.hpp library/data_structures_[l,r)/seg_tree_uncommon/walk.hpp renamed to library/data_structures_[l,r)/seg_tree_uncommon/max_right.hpp

@@ -1,4 +1,4 @@
-int walk(int l, int r, const auto& f) {
+int max_right(int l, int r, const auto& f) {
   for (T x = unit; l < r;) {
     int u = l + n, v = __lg(min(u & -u, r - l));
     if (T y = op(x, s[u >> v]); f(y)) l += 1 << v, x = y;

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

@@ -38,5 +38,5 @@ template<class T, class F> struct tree {
     while (l <= r) x = op(x, s[nxt(l, r)]);
     return x;
   }
-#include "seg_tree_uncommon/walk.hpp"
+#include "seg_tree_uncommon/max_right.hpp"
 };

…uctures_[l,r]/seg_tree_uncommon/walk.hpp …es_[l,r]/seg_tree_uncommon/max_right.hpplibrary/data_structures_[l,r]/seg_tree_uncommon/walk.hpp renamed to library/data_structures_[l,r]/seg_tree_uncommon/max_right.hpp library/data_structures_[l,r]/seg_tree_uncommon/walk.hpp renamed to library/data_structures_[l,r]/seg_tree_uncommon/max_right.hpp

@@ -1,4 +1,4 @@
-int walk(int l, int r, const auto& f) {
+int max_right(int l, int r, const auto& f) {
   if (T x = s[l + n]; f(x))
     for (l++; l <= r;) {
       int u = l + n, v = __lg(min(u & -u, r - l + 1));

library/graphs/euler_walk.hpp

@@ -0,0 +1,30 @@
+#pragma once
+//! @code
+//!   vector<basic_string<array<int, 2>>> adj(n);
+//!   vector<pii> edges(m);
+//!   r ep(i, 0, m) {
+//!     int u, v;
+//!     cin >> u >> v;
+//!     u--, v--;
+//!     adj[u] += {v, i};
+//!     edges[i] = {u, v};
+//!   }
+//!   vector<pii> path = euler_path(adj, m, source);
+//! @endcode
+//! @time O(n + m)
+//! @space O(n + m)
+vector<pii> euler_path(auto& adj, int m, int s) {
+  vi vis(m);
+  vector<pii> path;
+  auto dfs = [&](auto&& self, int u, int eu) -> void {
+    while (!empty(adj[u])) {
+      auto [v, ev] = adj[u].back();
+      adj[u].pop_back();
+      if (!vis[ev]) vis[ev] = 1, self(self, v, ev);
+    }
+    path.emplace_back(u, eu);
+  };
+  dfs(dfs, s, -1);
+  ranges::reverse(path);
+  return path;
+}

tests/library_checker_aizu_tests/data_structures/simple_tree_inc_walk.test.cpp

@@ -22,7 +22,7 @@ int main() {
       cout << st.query(k, k) << '\n';
     } else if (type == 3) {
       // returns first element in [k,n-1] such that sum > 0
-      int idx = st.walk(k, n - 1,
+      int idx = st.max_right(k, n - 1,
         [&](int sum) { return sum == 0; });
       if (idx == n) idx = -1;
       cout << idx << '\n';
@@ -32,7 +32,7 @@ int main() {
       if (total == 0) {
         cout << -1 << '\n';
       } else {
-        cout << st.walk(0, k, [&](int sum) {
+        cout << st.max_right(0, k, [&](int sum) {
           return sum < total;
         }) << '\n';
       }

tests/library_checker_aizu_tests/data_structures/simple_tree_walk.test.cpp

@@ -21,8 +21,8 @@ int main() {
       cout << st.query(k, k + 1) << '\n';
     } else if (type == 3) {
       // returns first element in [k,n) such that sum > 0
-      int idx =
-        st.walk(k, n, [&](int sum) { return sum == 0; });
+      int idx = st.max_right(k, n,
+        [&](int sum) { return sum == 0; });
       if (idx == n) idx = -1;
       cout << idx << '\n';
     } else {
@@ -31,7 +31,7 @@ int main() {
       if (total == 0) {
         cout << -1 << '\n';
       } else {
-        cout << st.walk(0, k + 1, [&](int sum) {
+        cout << st.max_right(0, k + 1, [&](int sum) {
           return sum < total;
         }) << '\n';
       }