99 lines
2.5 KiB
Rust
99 lines
2.5 KiB
Rust
#[derive(Debug)]
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struct Heap {
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data: Vec<Option<i32>>,
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capacity: usize,
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count: i32,
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}
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impl Heap {
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pub fn new(capacity: usize) -> Self {
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Heap {
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data: vec![None; capacity],
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capacity: capacity,
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count: 0
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}
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}
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pub fn insert(&mut self, x: i32) -> bool {
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// 堆已满
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if self.capacity as i32 == self.count { return false; }
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self.data[self.count as usize] = Some(x);
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if self.count == 0 {
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self.count += 1;
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return true;
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}
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let mut idx = self.count as usize;
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// 子节点大于父节点，子节点与父节点交换
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// 自底向上堆化
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let mut parent_idx = ((idx - 1) >> 1) as usize;
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while parent_idx > 0 && self.data[idx] > self.data[parent_idx] {
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self.swap(idx, parent_idx);
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idx = parent_idx;
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parent_idx = ((idx - 1) >> 1) as usize;
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}
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self.count += 1;
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true
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}
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pub fn remove_max(&mut self) -> Option<i32> {
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// 堆已空
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if self.count == 0 { return None; }
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let max_value = self.data[0];
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// 将最后一个叶子节点移至堆顶
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self.data[0] = self.data[(self.count - 1) as usize];
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self.data[(self.count - 1) as usize] = None;
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self.heapify();
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self.count -= 1;
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max_value
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}
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// 堆化，自上向下堆化
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fn heapify(&mut self) {
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let mut idx = 0usize;
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loop {
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let mut max_pos = idx;
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if (2 * idx + 1) as i32 <= self.count && self.data[idx] < self.data[2 * idx + 1] { max_pos = 2 * idx + 1; }
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if (2 * idx + 2) as i32 <= self.count && self.data[max_pos] < self.data[2 * idx + 2] { max_pos = 2 * idx + 2; }
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if max_pos == idx { break; }
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self.swap(idx, max_pos);
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idx = max_pos;
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}
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}
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fn swap(&mut self, idx: usize, parent_idx: usize) {
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let tmp = self.data[parent_idx];
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self.data[parent_idx] = self.data[idx];
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self.data[idx] = tmp;
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}
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}
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fn main() {
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let mut h = Heap::new(16);
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h.insert(33);
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h.insert(27);
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h.insert(21);
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h.insert(16);
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h.insert(13);
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h.insert(15);
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h.insert(9);
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h.insert(5);
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h.insert(6);
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h.insert(7);
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h.insert(8);
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h.insert(1);
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h.insert(2);
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h.insert(22);
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println!("{:?}", h);
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h.remove_max();
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println!("{:?}", h);
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h.remove_max();
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println!("{:?}", h);
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h.remove_max();
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println!("{:?}", h);
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}
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