Min binary heap using array representation. Examples: >>> heap = BinaryHeap() >>> heap.insert(5) >>> heap.insert(3) >>> heap.remove_min() 3
| 68 | |
| 69 | |
| 70 | class BinaryHeap(AbstractHeap): |
| 71 | """Min binary heap using array representation. |
| 72 | |
| 73 | Examples: |
| 74 | >>> heap = BinaryHeap() |
| 75 | >>> heap.insert(5) |
| 76 | >>> heap.insert(3) |
| 77 | >>> heap.remove_min() |
| 78 | 3 |
| 79 | """ |
| 80 | |
| 81 | def __init__(self) -> None: |
| 82 | """Initialize the binary heap with a sentinel at index 0.""" |
| 83 | self.current_size: int = 0 |
| 84 | self.heap: list[int] = [0] |
| 85 | |
| 86 | def perc_up(self, index: int) -> None: |
| 87 | """Percolate element up to maintain the min-heap invariant. |
| 88 | |
| 89 | Args: |
| 90 | index: Index of the element to percolate up. |
| 91 | """ |
| 92 | while index // 2 > 0: |
| 93 | if self.heap[index] < self.heap[index // 2]: |
| 94 | self.heap[index], self.heap[index // 2] = ( |
| 95 | self.heap[index // 2], |
| 96 | self.heap[index], |
| 97 | ) |
| 98 | index = index // 2 |
| 99 | |
| 100 | def insert(self, val: int) -> None: |
| 101 | """Insert a value into the heap. |
| 102 | |
| 103 | Args: |
| 104 | val: The value to insert. |
| 105 | """ |
| 106 | self.heap.append(val) |
| 107 | self.current_size = self.current_size + 1 |
| 108 | self.perc_up(self.current_size) |
| 109 | |
| 110 | def min_child(self, index: int) -> int: |
| 111 | """Return the index of the smaller child of a parent node. |
| 112 | |
| 113 | Args: |
| 114 | index: Index of the parent node. |
| 115 | |
| 116 | Returns: |
| 117 | Index of the smaller child. |
| 118 | """ |
| 119 | if 2 * index + 1 > self.current_size: |
| 120 | return 2 * index |
| 121 | if self.heap[2 * index] > self.heap[2 * index + 1]: |
| 122 | return 2 * index + 1 |
| 123 | return 2 * index |
| 124 | |
| 125 | def perc_down(self, index: int) -> None: |
| 126 | """Percolate element down to maintain the min-heap invariant. |
| 127 |