鍏堣涓涓婮DK 瀵筁ist鐨勯殢鏈烘帓搴忕殑瀹炵幇錛?/p>
public static void shuffle(List list, Random rnd) {銆銆銆銆
聽聽聽 銆銆final int SHUFFLE_THRESHOLD聽聽聽聽聽聽聽 =聽聽聽 5;銆銆//榪欏簲褰撴槸涓涓粡楠屽煎惂
聽聽聽聽聽聽聽 int size = list.size();
銆銆/** 涓轟粈涔堣鍒ゆ柇錛屽悗闈㈡湁璁鴻堪 */
聽聽聽聽聽聽聽 if (size < SHUFFLE_THRESHOLD || list instanceof RandomAccess) {
聽聽聽聽聽聽聽聽聽聽聽 for (int i=size; i>1; i--)
聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽 swap(list, i-1, rnd.nextInt(i));聽聽//榪欎竴縐嶆柟娉曟槸鐩存帴璋冪敤List.set鏂規(guī)硶錛屽睘浜嶳andomAccess涓殑鏂規(guī)硶
聽聽聽聽聽聽聽 } else {
聽聽聽聽聽聽聽聽聽聽聽 Object arr[] = list.toArray();
聽聽聽聽聽聽聽聽聽聽聽 // Shuffle array
聽聽聽聽聽聽聽聽聽聽聽 for (int i=size; i>1; i--)
聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽 swap(arr, i-1, rnd.nextInt(i));
聽聽聽聽聽聽聽聽聽聽聽 // Dump array back into list
聽聽聽聽聽聽聽聽聽聽聽 ListIterator it = list.listIterator();聽聽聽聽聽 //濡傛灉涓嶆槸Random Access瀹炵幇錛屽氨浣跨敤榪唬鍣ㄩ亶鍘?br />聽聽聽聽聽聽聽聽聽聽聽 for (int i=0; i<arr.length; i++) {
聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽 it.next();
聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽 it.set(arr[i]);
聽聽聽聽聽聽聽聽聽聽聽 }
聽聽聽聽聽聽聽 }
聽聽聽 }
鍐嶈涓涓嬫垜鑷繁鐨勭鎷欏疄鐜幫細(xì)
銆銆public static List randomSortList(List ls, Random random) {
聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽 List randomList = new ArrayList();聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽
聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽 int size = list.size();
聽聽聽聽聽聽聽聽聽聽聽聽聽聽 while (size > 0) {
聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽 int randomNum = random.nextInt(size);
聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽 randomList.add(ls.get(randomNum));
聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽 ls.remove(randomNum); //榪欎竴姝ワ紝瀵逛簬RandomAccess鐨勯泦鍚堟潵璇達(dá)紝鏄疧(1)鎿嶄綔
聽聽聽聽聽聽聽聽聽聽聽聽聽 聽}
聽聽聽聽聽聽聽聽聽聽聽聽聽聽 return randomList;
聽聽聽聽 }
璇勮堪錛?br />銆銆濡傛灉List鐨勫疄鐜版槸ArrayList錛屽湪鏃墮棿鏁堢巼涓婅澶氬驚鐜竴嬈★紝浣嗗湪絀洪棿涓婏紝鎴戠殑鏂規(guī)硶闈炲父宸紝澶氱敓鎴愪竴涓狶ist闆嗗悎錛屽鏋淟ist寰堝ぇ錛屽氨鏇村樊浜嗐傚悓鏃舵垜鐨勭畻娉曞鏋滅敤浜嶴equence List涓婏紝鏁堢巼鏄浉褰撶殑宸紝鍙兘閫傚悎ArrayList,鏈夊緢澶х殑灞闄愭с?br />銆銆榪欐槸鍥犱負(fù)錛?濡傛灉闆嗗悎綾繪槸RandomAccess鐨勫疄鐜幫紝鍒欏敖閲忕敤for(int i = 0; i < size; i++) 鏉ラ亶鍘嗚屼笉瑕佺敤Iterator榪唬鍣ㄦ潵閬嶅巻錛屽湪鏁堢巼涓婅宸竴浜涖傚弽榪囨潵錛屽鏋淟ist鏄疭equence List錛屽垯鏈濂界敤榪唬鍣ㄦ潵榪涜榪唬銆?br />銆銆JDK涓鐨勫緢娓呮錛屽湪瀵筁ist鐗瑰埆鏄疕uge size鐨凩ist鐨勯亶鍘嗙畻娉曚腑錛岃灝介噺鏉ュ垽鏂槸灞炰簬RandomAccess(濡侫rrayList)榪樻槸Sequence List (濡侺inkedList錛夛紝鍥犱負(fù)閫傚悎RandomAccess List鐨勯亶鍘嗙畻娉曪紝鐢ㄥ湪Sequence List涓婂氨宸埆寰堝ぇ錛屽父鐢ㄧ殑浣滄硶灝辨槸錛?br />聽聽聽 瑕佷綔涓涓垽鏂細(xì)
聽聽聽 if (list instance of RandomAccess) {
聽聽聽聽聽聽聽 for(int m = 0; m < list.size(); m++){}
聽聽聽 }else{
聽聽聽聽聽聽聽 Iterator iter = list.iterator();
聽聽聽聽聽聽聽 while(iter.hasNext()){}
聽聽聽 }
聽聽 鎴戠殑欏圭洰涓璍ist閮芥槸鍩轟簬ArrayList鐨勶紝鎵浠ュ熀鏈笂寰堝皯鐢ㄨ凱浠ｅ櫒鏉ラ亶鍘嗭紝鑰屾槸鐢╢or寰幆鏉ラ亶鍘嗭紝瀵逛簬榪唬鍣ㄧ殑浣滅敤鎴戝綋鐒跺緢娓呮錛屼絾鏄垜瑙夊緱鏈夌偣搴鎬漢鑷壈浜嗐?br />聽聽 闄ら潪浣犵粡甯哥敤Collection浣滀負(fù)浣犵殑鎺ュ彛鏂規(guī)硶涓殑杈撳叆鎴栬緭鍑虹殑闆嗗悎鍙傛暟綾誨瀷鏃訛紝浣犱篃灝卞彧鑳界敤Iterator銆?br />聽聽 浣嗘垜涓鑸湪鎺ュ彛鏂規(guī)硶涓紝涓鑸敤List錛屾墍浠ユ垜灝變笉鐢ㄨ凱浠ｅ櫒錛岄櫎闈炴垜鐨凩ist鏄疞inked List瀹炰緥銆?br />聽聽 濂界殑浣滄硶鏄細(xì)鍦ㄤ緵澶栭儴璋冪敤鐨勬帴鍙ｆ柟娉曚腑錛屼嬌鐢–ollection浣滀負(fù)闆嗗悎鍙傛暟綾誨瀷錛屽湪鍐呴儴瀹炵幇褰撲腑錛屼嬌鐢↙ist錛岃屼笉鏄竴鍛崇殑浣跨敤Collections鍙?qiáng)Iterator錛岃繖鏍峰仛鏃犲紓浜庝綔鑼?dǎo)鑷~氥?br />聽聽 欏轟究璇翠竴涓婮DK涓帹鑽愮殑鏄List闆嗗悎灝介噺瑕佸疄鐜癛andomAccess鎺ュ彛銆?br />