* 比较大小的类 ./utils/Comparator.js

https://blog.csdn.net/fareast_mzh/article/details/81810822

* BinarySearchTree.js

  基本版： https://blog.csdn.net/fareast_mzh/article/details/81746269 元素只能是Number类型

/**
 * Created by PhpStorm.
 * User: Mch
 * Date: 8/16/18
 * Time: 23:26
 */
var Comparator = require('./utils/Comparator.js').Comparator;

function Node(key) {
    this.key = key;
    this.left = null;
    this.right = null;
}

function BinarySearchTree(comparatorFunction) {
    this.root = null;
    this.comparator = new Comparator(comparatorFunction);
}

BinarySearchTree.prototype.insert = function(key) {
    var newNode = new Node(key);

    if (this.root === null) {
        this.root = newNode;
    } else {
        BinarySearchTree.insertNode(this.root, newNode, this.comparator);
    }
};

BinarySearchTree.insertNode = function(node, newNode, cmp) {
    if (cmp.lessThan(newNode.key, node.key)) {
        if (node.left === null) {
            node.left = newNode;
        } else {
            BinarySearchTree.insertNode(node.left, newNode, cmp);
        }
    } else {
        if (node.right === null) {
            node.right = newNode;
        } else {
            BinarySearchTree.insertNode(node.right, newNode, cmp);
        }
    }
};

BinarySearchTree.inOrderTraverseNode = function(node, callback) {
    if (node !== null) {
        BinarySearchTree.inOrderTraverseNode(node.left, callback);
        callback(node.key);
        BinarySearchTree.inOrderTraverseNode(node.right, callback);
    }
};

BinarySearchTree.prototype.inOrderTraverse = function(callback) {
    BinarySearchTree.inOrderTraverseNode(this.root, callback);
};

BinarySearchTree.findMinNode = function(node) {
    if (node) {
        while (node && node.left !== null) {
            node = node.left;
        }
        return node;
    }
    return null;
};

BinarySearchTree.prototype.min = function() {
    return BinarySearchTree.minNode(this.root);
};

BinarySearchTree.minNode = function(node) {
    if (node) {
        while (node && node.left !== null) {
            node = node.left;
        }
        return node.key;
    }
    return null;
};

BinarySearchTree.prototype.max = function() {
    return BinarySearchTree.maxNode(this.root);
};

BinarySearchTree.maxNode = function(node) {
    if (node) {
        while (node && node.right !== null) {
            node = node.right;
        }
        return node.key;
    }
    return null;
};

BinarySearchTree.prototype.search = function(key) {
    return BinarySearchTree.searchNode(this.root, key, this.comparator);
};

BinarySearchTree.searchNode = function(node, key, cmp) {
    if (node === null) {
        return false;
    }
    if (cmp.lessThan(key, node.key)) {
        return BinarySearchTree.searchNode(node.left, key, cmp);
    } else if (this.comparator.greaterThan(key, node.key)) {
        return BinarySearchTree.searchNode(node.right, key, cmp);
    }
    return true;
};

BinarySearchTree.prototype.remove = function(key) {
    this.root = BinarySearchTree.removeNode(this.root, key, this.comparator);
};

BinarySearchTree.removeNode = function(node, key, cmp) {
    if (node === null) {
        return null;
    }
    if (cmp.lessThan(key, node.key)) {
        node.left = BinarySearchTree.removeNode(node.left, key, cmp);
        return node;
    } else if (cmp.greaterThan(key, node.key)) {
        node.right = BinarySearchTree.removeNode(node.right, key, cmp);
        return node;
    } else {
        if (node.left === null && node.right === null) {
            node = null;
            return node;
        }
        if (node.left === null) {
            node = node.right;
            return node;
        } else if (node.right === null) {
            node = node.left;
            return node;
        }

        var aux = BinarySearchTree.findMinNode(node.right);
        node.key = aux.key;
        node.right = BinarySearchTree.removeNode(node.right, aux.key, cmp);
        return node;
    }

};

BinarySearchTree.prototype.toArray = function() {
    var a = [];
    this.inOrderTraverse(function(el) {
        a.push(el);
    });
    return a;
};

exports.BinarySearchTree = BinarySearchTree;

test:

var BinarySearchTree = require('./BinarySearchTree.js').BinarySearchTree;

var tree = new BinarySearchTree(function(a, b) {
    return a-b;
});

[7,15,5,3,9,8,10,13,11,12,14,20,18,25].forEach(function(el) {
        tree.insert(el);
});

console.log(tree.toArray());

console.log(tree.min());
console.log(tree.max());

tree.remove(14);
console.log(tree.toArray());
tree.remove(11);
tree.remove(3);
tree.remove(25);
console.log(tree.toArray());

$ node app.js
[ 3, 5, 7, 8, 9, 10, 11, 12, 13, 14, 15, 18, 20, 25 ]
3
25
[ 3, 5, 7, 8, 9, 10, 11, 12, 13, 15, 18, 20, 25 ]
[ 5, 7, 8, 9, 10, 12, 13, 15, 18, 20 ]