使用List
publicstaticbooleanreturn Arrays.asList(arr).contains(targetValue); }
使用Set
publicstaticsetnew HashSet<String>(Arrays.asList(arr)); returnset.contains(targetValue); }
使用循环判断
publicstaticbooleanforifreturntrue; } returnfalse; }
使用 Arrays.binarySearch()
publicstaticbooleanint a = Arrays.binarySearch(arr, targetValue); if0returntrue; elsereturnfalse; }
时间复杂度
publicstaticvoidnew"CD""BC""EF""DE""AB"}; //use listlong startTime = System.nanoTime(); forint0100000; i++) { useList(arr, ); } long endTime = System.nanoTime(); long duration = endTime - startTime; System.out"useList: "1000000); //use set startTime = System.nanoTime(); forint0100000; i++) { useSet(arr, ); } endTime = System.nanoTime(); duration = endTime - startTime; System.out"useSet: "1000000); //use loop startTime = System.nanoTime(); forint0100000; i++) { useLoop(arr, ); } endTime = System.nanoTime(); duration = endTime - startTime; System.out"useLoop: "1000000); //use Arrays.binarySearch() startTime = System.nanoTime(); forint0100000; i++) { useArraysBinarySearch(arr, ); } endTime = System.nanoTime(); duration = endTime - startTime; System.out"useArrayBinary: "1000000); }
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使用一个长度为1k的数组
new1000]; Random s = new Random(); forint01000; i++){ arr[i] = String.valueOf(s.nextInt()); }
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使用一个长度为10k的数组
new10000]; Random s = new Random(); forint010000; i++){ arr[i] = String.valueOf(s.nextInt()); }
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总结
Arrays.binarySearch()使用 ArrayUtils
ArrayUtilscontainsimport org.apache.commons.lang3.ArrayUtils; publicstaticbooleanreturn ArrayUtils.contains(arr,targetValue); }