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| 1 | +package TimSort; |
| 2 | + |
| 3 | +/** |
| 4 | + * |
| 5 | + * @author kdgyun |
| 6 | + * |
| 7 | + * @version 1.1.0 |
| 8 | + * @since 1.0.0 |
| 9 | + * |
| 10 | + * {@link https://st-lab.tistory.com} |
| 11 | + * {@link https://github.com/kdgyun} |
| 12 | + * |
| 13 | + */ |
| 14 | + |
| 15 | + |
| 16 | +public class TimSort { |
| 17 | + |
| 18 | + private static final int THRESHOLD = 32; |
| 19 | + public static void sort(int[] a) { |
| 20 | + sort(a, 0, a.length); |
| 21 | + } |
| 22 | + |
| 23 | + public static void sort(int[] a, int lo, int hi) { |
| 24 | + |
| 25 | + int remain = lo - hi; |
| 26 | + if(remain < 2) { |
| 27 | + return; |
| 28 | + } |
| 29 | + |
| 30 | + /** |
| 31 | + * 일정 크기 이하의 배열이라면 |
| 32 | + * binaryInsertionSort로 정렬 |
| 33 | + * |
| 34 | + * @see BinaryInsertionSort.BinaryInsertionSort |
| 35 | + */ |
| 36 | + if(remain < THRESHOLD) { |
| 37 | + int increaseRange = getAscending(a, lo, hi); |
| 38 | + BinarySort(a, lo, hi, lo + increaseRange); |
| 39 | + } |
| 40 | + } |
| 41 | + |
| 42 | + private static void BinarySort(int[] a, int lo, int hi ,int start) { |
| 43 | + |
| 44 | + if(lo == start) { |
| 45 | + start++; |
| 46 | + } |
| 47 | + |
| 48 | + for (; start < hi; start++) { |
| 49 | + int target = a[start]; |
| 50 | + |
| 51 | + int loc = binarySearch(a, target, 0, start); |
| 52 | + |
| 53 | + int j = start - 1; |
| 54 | + |
| 55 | + while (j >= loc) { |
| 56 | + a[j + 1] = a[j]; |
| 57 | + j--; |
| 58 | + } |
| 59 | + |
| 60 | + a[loc] = target; |
| 61 | + } |
| 62 | + } |
| 63 | + |
| 64 | + private static int binarySearch(int[] a, int key, int lo, int hi) { |
| 65 | + |
| 66 | + int mid; |
| 67 | + while (lo < hi) { |
| 68 | + mid = (lo + hi) >>> 1; |
| 69 | + if (key < a[mid]) { |
| 70 | + hi = mid; |
| 71 | + } |
| 72 | + else { |
| 73 | + lo = mid + 1; |
| 74 | + } |
| 75 | + } |
| 76 | + return lo; |
| 77 | + } |
| 78 | + |
| 79 | + private static int getAscending(int[] a, int lo, int hi) { |
| 80 | + |
| 81 | + int limit = lo + 1; |
| 82 | + if (limit == hi) { |
| 83 | + return 1; |
| 84 | + } |
| 85 | + |
| 86 | + if (a[lo] <= a[limit]) { |
| 87 | + while (limit < hi && a[limit - 1] <= a[limit]) { |
| 88 | + limit++; |
| 89 | + } |
| 90 | + } |
| 91 | + else { |
| 92 | + while (limit < hi && a[limit - 1] > a[limit]) { |
| 93 | + limit++; |
| 94 | + } |
| 95 | + reversing(a, lo, limit); |
| 96 | + } |
| 97 | + |
| 98 | + return limit - lo; |
| 99 | + } |
| 100 | + |
| 101 | + private static void reversing(int[] a, int lo, int hi) { |
| 102 | + hi--; |
| 103 | + while (lo < hi) { |
| 104 | + int temp = a[lo]; |
| 105 | + a[lo++] = a[hi]; |
| 106 | + a[hi--] = temp; |
| 107 | + } |
| 108 | + } |
| 109 | +} |
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