# 图灵学院JAVA高级架构师【第四期】

public class Sort {
public static <AnyType extends Comparable<? super AnyType>> void insertionSort(AnyType[] a) {

``insertionSort(a, 0, a.length - 1);``

}

private static <AnyType extends Comparable<? super AnyType>> void insertionSort(AnyType[] a, int left, int right) {

``````int j;  // 记录第一个比tmp小的元素的后边一位的位置

for (int p = left; p <= right; p++) {
AnyType tmp = a[p];
for (j = p; j > left && tmp.compareTo(a[j - 1]) < 0; j--) {
a[j] = a[j - 1];
}
a[j] = tmp;
}``````

}

public static <AnyType extends Comparable<? super AnyType>> void shellSort(AnyType[] arr) {

``````int j;

for (int gap = arr.length / 2; gap > 0; gap /= 2) {
for (int i = gap; i < arr.length; i++) {
AnyType tmp = arr[i];
for (j = i; j >= gap && tmp.compareTo(arr[j - gap]) < 0; j -= gap) {
arr[j] = arr[j - gap];
}
arr[j] = tmp;
}
}``````

}

private static int leftChild(int i) {

``return i * 2 + 1;``

}

private static <AnyType extends Comparable<? super AnyType>> void perculateDown(AnyType[] arr, int i, int size) {

``````AnyType tmp = arr[i];

for (int child; (child = leftChild(i)) < size; i = child) {
if (child != size - 1 && arr[child].compareTo(arr[child + 1]) < 0) {
child++;
}
if (tmp.compareTo(arr[child]) < 0) {
arr[i] = arr[child];
} else {
break;
}
}
arr[i] = tmp;``````

}

public static <AnyType extends Comparable<? super AnyType>> void heapSort(AnyType[] arr) {

``````for (int i = arr.length / 2; i >= 0; i--) {
perculateDown(arr, i, arr.length);
}
for (int i = arr.length - 1; i >= 0; i--) {
swapReferences(arr, 0, i);
perculateDown(arr, 0, i);
}``````

}

private static <AnyType extends Comparable<? super AnyType>> void swapReferences(AnyType[] arr, int i, int j) {

``````AnyType tmp = arr[i];
arr[i] = arr[j];
arr[j] = tmp;``````

}

public static <AnyType extends Comparable<? super AnyType>> void mergeSort(AnyType[] arr) {

``````AnyType[] tmp = ((AnyType[]) new Comparable[arr.length]);
mergeSort(arr, 0, arr.length - 1, tmp);``````

}

private static <AnyType extends Comparable<? super AnyType>> void mergeSort(AnyType[] arr, int start, int end, AnyType[] tmp) {

``````if (start < end) {
int mid = (start + end) >> 1;
mergeSort(arr, start, mid, tmp);
mergeSort(arr, mid + 1, end, tmp);
merge(arr, start, mid, end, tmp);
}``````

}

private static <AnyType extends Comparable<? super AnyType>> void merge(AnyType[] arr, int start, int mid, int end, AnyType[] tmp) {

``````int i = start, j = mid + 1, k = start;
while (i <= mid && j <= end) {
if (arr[i].compareTo(arr[j]) < 0) {
tmp[k++] = arr[i++];
} else {
tmp[k++] = arr[j++];
}
}

while (i <= mid) {
tmp[k++] = arr[i++];
}

while (j <= end) {
tmp[k++] = arr[j++];
}

for (int m = start; m <= end; m++) {
arr[m] = tmp[m];
}``````

}

public static <AnyType extends Comparable<? super AnyType>> void quickSort(AnyType[] arr) {

``quickSort(arr, 0, arr.length - 1);``

}

private static <AnyType extends Comparable<? super AnyType>> void quickSort(AnyType[] arr, int left, int right) {

``````if (left + LENGTH_DIFF <= right) {

AnyType pivot = medium(arr, left, right);

int i = left, j = right;
while (true) {
while (arr[++i].compareTo(pivot) < 0);
while (arr[--j].compareTo(pivot) > 0);

if (i < j) {
swapReferences(arr, i, j);
} else {
break;
}
}

swapReferences(arr, i, right);
quickSort(arr, left, i - 1);
quickSort(arr, i + 1, right);
} else {
insertionSort(arr, left, right);
}``````

}

private static <AnyType extends Comparable<? super AnyType>> AnyType medium(AnyType[] arr, int left,

``````  int right) {
int center = (left + right) / 2;
if (arr[center].compareTo(arr[left]) < 0) {
swapReferences(arr, center, left);
}
if (arr[left].compareTo(arr[right]) > 0) {
swapReferences(arr, left, right);
}
if (arr[center].compareTo(arr[right]) < 0) {
swapReferences(arr, center, right);
}

return arr[right];``````

}

private final static int LENGTH_DIFF = 20;
}

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