- A+
所属分类：Web前端
HashMap代码(有问题的代码，有没有大神可以指出问题在哪？)：
/** * HashMap * 2021年09月09日 */ (function (global) { var _map; var _length; global.HashMap = function () { _map = {}; _length = 0; }; global.HashMap.prototype = { put: function (key, value) { if (!_map.hasOwnProperty(key)) { _length++; } _map[key] = value; }, get: function (key) { if (_map.hasOwnProperty(key)) { return _map[key]; } return null; }, containsKey: function (key) { return _map.hasOwnProperty(key); }, size: function () { return _length; }, remove: function (key) { if (_map.hasOwnProperty(key)) { _length--; return delete _map[key]; } return false; }, removeAll: function () { _map = {}; }, keys: function () { var keys = []; for (var item in _map) { keys.push(item); } return keys; }, values: function () { var values = []; for (var item in _map) { values.push(_map[item]); } return values; } }; global.HashMap.prototype.constructor = global.HashMap; })(window);
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HashMap代码：
/** * HashMap * 2021年09月09日 */ HashMap = function () { this._length = 0; this._map = {}; }; HashMap.prototype = { put: function (key, value) { if (!this._map.hasOwnProperty(key)) { this._length++; } this._map[key] = value; }, get: function (key) { if (this._map.hasOwnProperty(key)) { return this._map[key]; } return null; }, containsKey: function (key) { return this._map.hasOwnProperty(key); }, size: function () { return this._length; }, remove: function (key) { if (this._map.hasOwnProperty(key)) { this._length--; return delete this._map[key]; } return false; }, removeAll: function () { this._length = 0; this._map = {}; }, keys: function () { var keys = []; for (var item in this._map) { keys.push(item); } return keys; }, values: function () { var values = []; for (var item in this._map) { values.push(this._map[item]); } return values; } }; HashMap.prototype.constructor = HashMap;
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测试代码：
<!DOCTYPE html> <html> <head> <title>HashMap测试</title> <meta charset="utf-8" /> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1"> <style type="text/css"> </style> <script type="text/javascript" src="jquery-1.7.1.js"></script> <script type="text/javascript" src="hashmap.js"></script> </head> <body> <input type="button" value="测试1" onclick="testHashMap()" /> <input type="button" value="测试2" onclick="testArray()" /> <div id="div" style="height:800px;"></div> <script type="text/javascript"> var n = 100000; var div = $("#div"); //测试数据 debugger; var list = []; var map = new HashMap(); for (var i = 1; i <= n; i++) { var val = Math.floor(Math.random() * n); var key = "key" + val; if (!map.containsKey(key)) { map.put(key, val); list.push({ key: key, value: val }); } } div.append("测试数据初始化完成，数据量：Array " + list.length + "，HashMap " + map.size() + "<br />"); //测试HashMap function testHashMap() { var t1 = new Date().getTime(); var sum = 0; var count = 0; for (var i = 20000; i <= 21000; i++) { var key = "key" + i; if (map.containsKey(key)) { var num = map.get(key); count++; sum += num; } } var t2 = new Date().getTime(); div.append("完成，结果：sum=" + sum + "，count=" + count + "耗时" + (t2 - t1).toString() + "毫秒<br />"); } //测试Array function testArray() { var t1 = new Date().getTime(); var sum = 0; var count = 0; for (var i = 20000; i <= 21000; i++) { for (var k = 0; k < list.length; k++) { var key = "key" + i; var item = list[k]; if (item.key == key) { count++; sum += item.value; } } } var t2 = new Date().getTime(); div.append("完成，结果：sum=" + sum + "，count=" + count + "耗时" + (t2 - t1).toString() + "毫秒<br />"); } </script> </body> </html>
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