const Compare = {
    LESS_THAN: -1,
    BIGGER_THAN: 1
}
function defaultCompare(a, b) {
    if (a === b) {
        return 0
    }
    return a < b ? Compare.LESS_THAN : Compare.BIGGER_THAN
}
class Node {
    constructor(key) {
        this.key = key
        this.left = null
        this.right = null
    }
}
class BinarySearchTree {
    constructor(compareFn = defaultCompare) {
        this.compareFn = compareFn
        this.root = null
    }
    /* 插入一个键 */
    insert(key) {
        if (this.root == null) {
            this.root = new Node(key)
        } else {
            this.insertNode(this.root, key)
        }
    }
    insertNode(node, key) {
        if (this.compareFn(key, node.key) === Compare.LESS_THAN) {
            if (node.left == null) {
                node.left = new Node(key)
            } else {
                this.insertNode(node.left, key)
            }
        } else {
            if (node.right == null) {
                node.right = new Node(key)
            } else {
                this.insertNode(node.right, key)
            }
        }
    }
    /* 中序遍历 */
    inOrderTraverse(callback) {
        this.inOrderTraverseNode(this.root, callback)
    }
    inOrderTraverseNode(node, callback) {
        if (node != null) {
            this.inOrderTraverseNode(node.left, callback)
            callback(node.key)
            this.inOrderTraverseNode(node.right, callback)
        }
    }
    /* 前序遍历 */
    preOrderTraverse(callback) {
        this.preOrderTraverseNode(this.root, callback)
    }
    preOrderTraverseNode(node, callback) {
        if (node != null) {
            callback(node.key)
            this.preOrderTraverseNode(node.left, callback)
            this.preOrderTraverseNode(node.right, callback)
        }
    }
    /* 后序遍历 */
    postOrderTraverse(callback) {
        this.postOrderTraverseNode(this.root, callback)
    }
    postOrderTraverseNode(node, callback) {
        if (node != null) {
            this.postOrderTraverseNode(node.left, callback)
            this.postOrderTraverseNode(node.right, callback)
            callback(node.key)
        }
    }
    /* 寻找树的最小键 */
    min() {
        return this.minNode(this.root)
    }
    minNode(node) {
        let current = node
        while (current != null && current.left != null) {
            current = current.left
        }
        return current
    }
    /* 寻找树的最大键 */
    max() {
        return this.maxNode(this.root)
    }
    maxNode(node) {
        let current = node
        while (current != null && current.right != null) {
            current = current.right
        }
        return current
    }
    /* 搜索一个特定的值 */
    search(key) {
        return this.searchNode(this.root, key)
    }
    searchNode(node, key) {
        if (node == null) {
            return false
        }
        if (this.compareFn(key, node.key) === Compare.LESS_THAN) {
            return this.searchNode(this.left, key)
        } else if (this.compareFn(key, node.key) === Compare.BIGGER_THAN) {
            return this.searchNode(node.right, key)
        } else {
            return true
        }
    }
    /* 移除一个节点 */
    remove(key) {
        this.root = this.removeNode(this.root, key)
    }
    removeNode(node, key) {
        if (node == null) {
            return null
        }
        if (this.compareFn(key, node.key) === Compare.LESS_THAN) {
            node.left = this.removeNode(node.left, key)
            return node
        } else if (this.compareFn(key, node.key) === Compare.BIGGER_THAN) {
            node.right = this.removeNode(node.right, key)
            return node
        } else {
            // 键等于 node.key
            // 第一种情况
            if (node.left == null && node.right == null) {
                node = null
                return node
            }
            // 第二种情况
            if (node.left == null) {
                node = node.right
                return node
            } else if (node.right == null) {
                node = node.left
                return node
            }
            //第三种情况
            const aux = this.minNode(node.right)
            node.key = aux.key
            node.right = this.removeNode(node.right, aux.key)
            return node
        }
    }
}