/* This file is part of TON Blockchain Library. TON Blockchain Library is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 2 of the License, or (at your option) any later version. TON Blockchain Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with TON Blockchain Library. If not, see . Copyright 2017-2019 Telegram Systems LLP */ #pragma once #include "td/utils/common.h" namespace td { struct HeapNode { bool in_heap() const { return pos_ != -1; } bool is_top() const { return pos_ == 0; } void remove() { pos_ = -1; } int pos_ = -1; }; template class KHeap { public: bool empty() const { return array_.empty(); } size_t size() const { return array_.size(); } KeyT top_key() const { return array_[0].key_; } HeapNode *pop() { CHECK(!empty()); HeapNode *result = array_[0].node_; result->remove(); erase(0); return result; } void insert(KeyT key, HeapNode *node) { CHECK(!node->in_heap()); array_.push_back({key, node}); fix_up(static_cast(array_.size()) - 1); } void fix(KeyT key, HeapNode *node) { CHECK(node->in_heap()); int pos = node->pos_; KeyT old_key = array_[pos].key_; array_[pos].key_ = key; if (key < old_key) { fix_up(pos); } else { fix_down(pos); } } void erase(HeapNode *node) { CHECK(node->in_heap()); int pos = node->pos_; node->remove(); erase(pos); } template void for_each(F &&f) const { for (auto &it : array_) { f(it.key_, it.node_); } } template void for_each(F &&f) { for (auto &it : array_) { f(it.key_, it.node_); } } void check() const { for (size_t i = 0; i < array_.size(); i++) { for (size_t j = i * K + 1; j < i * K + 1 + K && j < array_.size(); j++) { CHECK(array_[i].key_ <= array_[j].key_); } } } private: struct Item { KeyT key_; HeapNode *node_; }; vector array_; void fix_up(int pos) { auto item = array_[pos]; while (pos) { int parent_pos = (pos - 1) / K; auto parent_item = array_[parent_pos]; if (parent_item.key_ < item.key_) { break; } parent_item.node_->pos_ = pos; array_[pos] = parent_item; pos = parent_pos; } item.node_->pos_ = pos; array_[pos] = item; } void fix_down(int pos) { auto item = array_[pos]; while (true) { int left_pos = pos * K + 1; int right_pos = min(left_pos + K, static_cast(array_.size())); int next_pos = pos; KeyT next_key = item.key_; for (int i = left_pos; i < right_pos; i++) { KeyT i_key = array_[i].key_; if (i_key < next_key) { next_key = i_key; next_pos = i; } } if (next_pos == pos) { break; } array_[pos] = array_[next_pos]; array_[pos].node_->pos_ = pos; pos = next_pos; } item.node_->pos_ = pos; array_[pos] = item; } void erase(int pos) { array_[pos] = array_.back(); array_.pop_back(); if (pos < static_cast(array_.size())) { fix_down(pos); fix_up(pos); } } }; } // namespace td