| 27 | } |
| 28 | |
| 29 | fn insert(&mut self, val: T) -> (bool, bool) { |
| 30 | let ret = match *self { |
| 31 | Null => { // 没有节点，直接插入 |
| 32 | let node = AvlNode { |
| 33 | val: val, |
| 34 | left: Null, |
| 35 | right: Null, |
| 36 | bfactor: 0, |
| 37 | }; |
| 38 | *self = Tree(Box::new(node)); |
| 39 | (true, true) |
| 40 | }, |
| 41 | Tree(ref mut node) => match node.val.cmp(&val) { |
| 42 | // 比较节点值，再判断该从哪边插入 |
| 43 | // inserted 表示是否插入 |
| 44 | // deepened 表示是否加深 |
| 45 | Equal => (false, false), // 相等，无需插入 |
| 46 | Less => { // 比节点数据大，插入右边 |
| 47 | let (inserted, deepened) = node.right.insert(val); |
| 48 | if deepened { |
| 49 | let ret = match node.bfactor { |
| 50 | -1 => (inserted, false), |
| 51 | 0 => (inserted, true), |
| 52 | 1 => (inserted, false), |
| 53 | _ => unreachable!(), |
| 54 | }; |
| 55 | node.bfactor += 1; |
| 56 | ret |
| 57 | } else { |
| 58 | (inserted, deepened) |
| 59 | } |
| 60 | }, |
| 61 | Greater => { // 比节点数据小，插入左边 |
| 62 | let (inserted, deepened) = node.left.insert(val); |
| 63 | if deepened { |
| 64 | let ret = match node.bfactor { |
| 65 | -1 => (inserted, false), |
| 66 | 0 => (inserted, true), |
| 67 | 1 => (inserted, false), |
| 68 | _ => unreachable!(), |
| 69 | }; |
| 70 | node.bfactor -= 1; |
| 71 | ret |
| 72 | } else { |
| 73 | (inserted, deepened) |
| 74 | } |
| 75 | }, |
| 76 | }, |
| 77 | }; |
| 78 | self.rebalance(); |
| 79 | |
| 80 | ret |
| 81 | } |
| 82 | |
| 83 | // 调整各节点的平衡因子 |
| 84 | fn rebalance(&mut self) { |