| 15 | self.wait(100) |
| 16 | |
| 17 | class SegmentTreeDiffScene(AlgoScene): |
| 18 | def __init__(self, **kwargs): |
| 19 | super().__init__(**kwargs) |
| 20 | self.datas = np.array([1, 2, 3, 4, 5, 6]) |
| 21 | self.group = [] |
| 22 | for i in range(self.datas.shape[0]): |
| 23 | self.group.append(i) |
| 24 | |
| 25 | def show_diff(self): |
| 26 | self.show_message("首先，让我们来看看区间问题的常见3个解法") |
| 27 | |
| 28 | table = AlgoTable(self, np.array([ |
| 29 | ["", "区间求和", "区间最大值", "区间修改", "单点修改"], |
| 30 | ["前缀和", AlgoCheckmark(), AlgoExmark(), AlgoExmark(), AlgoExmark(),], |
| 31 | ["树状数组", AlgoCheckmark(), AlgoCheckmark(), AlgoExmark(), AlgoCheckmark(),], |
| 32 | ["线段树", AlgoCheckmark(), AlgoCheckmark(), AlgoCheckmark(), AlgoCheckmark(),], |
| 33 | ], dtype=object)) |
| 34 | |
| 35 | self.play(ShowCreation(table), run_time=4) |
| 36 | |
| 37 | rect = SurroundingRectangle(table) |
| 38 | self.play(ShowCreation(rect)) |
| 39 | |
| 40 | self.show_message("前缀和、树状数组、线段树") |
| 41 | |
| 42 | self.show_message("前缀和一般用于固定的数组") |
| 43 | |
| 44 | self.show_message("树状数组是一种很高效的数据结构") |
| 45 | self.show_message("功能能满足大部分需求") |
| 46 | |
| 47 | self.show_message("线段树则是一种非常灵活的数据结构") |
| 48 | self.show_message("本动画重点讲解线段树") |
| 49 | self.play(FadeOut(table), FadeOut(rect)) |
| 50 | |
| 51 | def what_is_segment_tree(self): |
| 52 | self.show_message("线段树是一棵树") |
| 53 | |
| 54 | self.show_message("从数组进行构造") |
| 55 | |
| 56 | array = AlgoVector(self, self.datas) |
| 57 | self.play(ShowCreation(array)) |
| 58 | self.play(array.to_edge, LEFT) |
| 59 | |
| 60 | # |
| 61 | tree = AlgoSegTree(self, self.datas) |
| 62 | self.play(ShowCreation(tree)) |
| 63 | self.play(tree.to_edge, RIGHT) |
| 64 | |
| 65 | def construct(self): |
| 66 | self.start_logo() |
| 67 | self.init_message("线段树") |
| 68 | self.show_diff() |
| 69 | # |
| 70 | self.wait(1) |
| 71 | |
| 72 | class SegmentTreeWhatIs(AlgoScene): |
| 73 | def __init__(self, **kwargs): |
nothing calls this directly
no outgoing calls
no test coverage detected