Java 实现各种排序算法并测试排序效率
public static void bubbleSort(int a[]) {
int len = a.length;
for (int i = 0; i < len - 1; i++) {
for (int j = 0; j < len - 1 - i; j++) {
if (a[j] > a[j + 1]) {
int temp = a[j];
a[j] = a[j + 1];
a[j + 1] = temp;
}
}
}
}
public static void selectSort(int a[]) {
int temp = 0;
int len = a.length;
for (int i = 0; i < len - 1; i++) {
int min = a[i];
int index = i;
for (int j = i + 1; j < len; j++) {
if (min > a[j]) {
min = a[j];
index = j;
}
}
temp = a[i];
a[i] = a[index];
a[index] = temp;
}
}
public static void insertSort(int a[]) {
int len = a.length;
for (int i = 1; i < len; i++) {
int temp = a[i];// 待插入的值
int index = i;// 待插入的位置
while (index > 0 && a[index - 1] > temp) {
a[index] = a[index - 1];// 待插入的位置重新赋更大的值
index--;// 位置往前移
}
a[index] = temp;
}
}
public static int partition(int a[], int low, int height) {
int key = a[low];
while (low < height) {
while (low < height && a[height] >= key)
height--;
a[low] = a[height];
while (low < height && a[low] <= key)
low++;
a[height] = a[low];
}
a[low] = key;
return low;
}
public static void quickSort(int a[], int low, int height) {
if (low < height) {
int result = partition(a, low, height);
quickSort(a, low, result - 1);
quickSort(a, result + 1, height);
}
}
测试结果
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测试数据10000
冒泡排序：120ms
选择排序：32ms
插入排序：20ms
快速排序：7ms
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测试数据100000
冒泡排序：13098ms
选择排序：2334ms
插入排序：1264ms
快速排序：23ms
效率差距很大啊！！！！