java排序算法-选择排序

时间:2022-08-08 23:07:40
public class SelectionSort {

	private static void selectSortTest() {
int[] sortArray = { 5, 2, 4, 1, 3 };
System.out.print("选择排序前: ");
Utils.printArray(sortArray);
selectSort(sortArray);
System.out.print("选择排序后: ");
Utils.printArray(sortArray);
} public static void selectSort(int[] sort) {
int temp;
for (int i = 0; i < sort.length - 1; i++) {
for (int j = i + 1; j < sort.length; j++) {
if (sort[i] > sort[j]) {
temp = sort[i];
sort[i] = sort[j];
sort[j] = temp;
}
}
}
} public static void heapSortTest(){
int[] arr = { 5, 2, 4, 1, 3 };
Utils.printArray("堆排序前:",arr);
heapSort(arr);
Utils.printArray("堆排序后:",arr);
} public static void heapSort(int[] arr) {
int arrLen = arr.length;
int temp = 0; //建立堆
for (int i = (arrLen-1) / 2; i >= 0; i--)
adjustHeap(arr, i, arrLen); //调整堆
for (int i = arrLen - 2; i >= 0; i--) {
temp = arr[i + 1];
arr[i + 1] = arr[0];
arr[0] = temp;
adjustHeap(arr, 0, i + 1); // Utils.printArray("第"+(9-i)+"次调整:",arr);
}
} public static void adjustHeap(int[] arr, int ri, int n) {
int temp = arr[ri];
int ci = 2 * ri + 1;
while (ci <= n - 1) {
if (ci < n - 1 && arr[ci] < arr[ci + 1])
ci++; if (temp >= arr[ci])
break;
arr[(ci - 1) / 2] = arr[ci];
ci = 2 * ci + 1;
}
arr[(ci - 1) / 2] = temp;
} public static void main(String [] args){
selectSortTest();
heapSortTest();
}
}