public class Sort {
/**
* 选择排序
*
* @param a
*/
public void selectSort(int[] a) {
int index;
int temp;
int len = a.length;
for (int i = 0; i < len - 1; i++) {
index = 0;
for (int j = 0; j < len - i; j++) {
if (a[index] < a[j]) {
index = j;
}
}
temp = a[index];
a[index] = a[len - i - 1];
a[len - i - 1] = temp;
}
}
/**
* 冒泡排序: 小至大
*
* @param a
*/
public void bubbleSort(int[] a) {
for (int j = 0; j < a.length; j++) {
for (int i = 0; i < a.length - j - 1; i++) {
if (a[i] > a[i + 1]) {
// 使用异或换值
// a[i+1] = a[i+1] ^ a[i] ;
// a[i] = a[i+1] ^ a[i] ;
// a[i+1] = a[i+1] ^ a[i] ;
// 使用中间变量换值
// int temp = a[i+1];
// a[i+1] = a[i];
// a[i] = temp;
a[i + 1] = a[i + 1] + a[i];
a[i] = a[i + 1] - a[i];
a[i + 1] = a[i + 1] - a[i];
}
}
}
}
/**
* 直接插入排序: 小至大
*
* @param
*/
public void straightInsertSort(int[] a) {
int temp;
for (int i = 1; i < a.length; i++) {
temp = a[i];
for (int j = i - 1; j >= 0; j--) {
if (a[j] > temp) {
a[j + 1] = a[j];
} else {
a[j + 1] = temp;
break;
}
}
}
}
/**
* 与straightInsertShort原理差不多,只是在寻找插入点时使用了二分查找
*
* @param a
*/
public void binaryInsertSort(int[] a) {
for (int i = 1; i < a.length; i++) {
int low = 0;
int hight = i - 1;
int temp = a[i];
while (low <= hight) {
int mid = (low + hight) / 2;
if (a[mid] < temp) {
low = mid + 1;
} else {
hight = mid - 1;
}
}
for (int j = i - 1; j >= low; j--) {
a[j + 1] = a[j];
}
a[low] = temp;
}
}
/**
* 快速排序 :小至大 思路: 选择一个基准元素,通过一趟扫描,(比大小)将待排序分成两个部分,然后对分好的两部分递归使用快排
*
* @param a
* @param star
* @param end
*/
public void quickSort(int[] a, int star, int end) {
int i = star;
int j = end;
int m = a[i];
while (i < j) {
while (a[j] > m && j > i) {
j--;
}
if (j > i) {
a[i] = a[j];
i++;
}
while (a[i] < m && j > i) {
i++;
}
if (j > i) {
a[j] = a[i];
j--;
}
}
a[i] = m;
if (i - 1 > star) {
quickSort(a, star, i - 1);
}
if (i + 1 < end) {
quickSort(a, i + 1, end);
}
}
/**
* 堆排序
*
* @param a
*/
public void heapSort(int[] a) {
int k;
int len = a.length;
for (int i = 0; i < len - 1; i++) {
k = createHeap(a, len - i - 1);
swap(a, 0, len - i - 1);
}
}
// 创建大根堆,取出最大值
public int createHeap(int[] a, int lastIndex) {
int k = 0;
for (int i = (lastIndex - 1) / 2; i >= 0; i--) {
// 从最后一个父节点开始,将其位置赋给 k
k = i;
while (2 * k + 1 <= lastIndex) {
// 判断 k 父节点是否有右子节点
int biggerIndex = 2 * k + 1;
if (2 * k + 1 < lastIndex) {
// 若有右子节点,取出大者
if (a[2 * k + 1] < a[2 * k + 2]) {
biggerIndex += 1;
}
}
if (a[biggerIndex] > a[k]) {
swap(a, biggerIndex, k);
k = biggerIndex;
} else {
break;
}
}
}
return k;
}
// 换值
public void swap(int[] a, int pos1, int pos2) {
a[pos1] = a[pos1] + a[pos2];
a[pos2] = a[pos1] - a[pos2];
a[pos1] = a[pos1] - a[pos2];
}
}
数组排序: 几种排序算法
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转载自blog.csdn.net/qq_41936045/article/details/81047000
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