| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #ifndef MIN_HEAP_H_ |
| #define MIN_HEAP_H_ |
| |
| #include "NativeTask.h" |
| #include "lib/Buffers.h" |
| |
| template<typename T, typename Compare> |
| void heapify(T* first, int rt, int heap_len, Compare & Comp) { |
| while (rt * 2 <= heap_len) // not leaf |
| { |
| int left = (rt << 1); // left child |
| int right = (rt << 1) + 1; // right child |
| int smallest = rt; |
| if (Comp(*(first + left - 1), *(first + smallest - 1))) { |
| smallest = left; |
| } |
| if (right <= heap_len && Comp(*(first + right - 1), *(first + smallest - 1))) { |
| smallest = right; |
| } |
| if (smallest != rt) { |
| std::swap(*(first + smallest - 1), *(first + rt - 1)); |
| rt = smallest; |
| } else { |
| break; |
| } |
| } |
| } |
| |
| template<typename T, typename Compare> |
| void makeHeap(T* begin, T* end, Compare & Comp) { |
| int heap_len = end - begin; |
| if (heap_len >= 0) { |
| for (uint32_t i = heap_len / 2; i >= 1; i--) { |
| heapify(begin, i, heap_len, Comp); |
| } |
| } |
| } |
| |
| template<typename T, typename Compare> |
| void popHeap(T* begin, T* end, Compare & Comp) { |
| *begin = *(end - 1); |
| // adjust [begin, end - 1) to heap |
| heapify(begin, 1, end - begin - 1, Comp); |
| } |
| |
| #endif /* HEAP_H_ */ |
