关于java:迈向高级的Java面试突围课资源分享

26次阅读

共计 2543 个字符，预计需要花费 7 分钟才能阅读完成。

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地位

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;}
  }

正文完