| 76 | } |
| 77 | |
| 78 | fn insert(&mut self, mut index: usize, elem: T) { |
| 79 | if index >= self.size { index = self.size; } |
| 80 | |
| 81 | // 分三种情况插入新节点 |
| 82 | let mut node = Node::new(elem); |
| 83 | if self.is_empty() { // LVec 为空 |
| 84 | self.head = Some(Box::new(node)); |
| 85 | } else if index == 0 { // 插入链表首部 |
| 86 | node.next = self.head.take(); |
| 87 | self.head = Some(Box::new(node)); |
| 88 | } else { // 插入链表中间 |
| 89 | let mut curr = self.head.as_mut().unwrap(); |
| 90 | for _i in 0..index - 1 { // 找到插入位置 |
| 91 | curr = curr.next.as_mut().unwrap(); |
| 92 | } |
| 93 | node.next = curr.next.take(); |
| 94 | curr.next = Some(Box::new(node)); |
| 95 | } |
| 96 | self.size += 1; |
| 97 | } |
| 98 | |
| 99 | fn pop(&mut self) -> Option<T> { |
| 100 | self.remove(self.size - 1) |