标签：integer math 大小 str main 初始化 判断 turn 最大的
public class BubbleSort {
public static void main(String[] args) {
int[] arr = {3, 4, 2, 9, 10, 15, 11, 0, 1};
System.out.println(Arrays.toString(bubbleSort(arr)));
}
public static int[] bubbleSort(int[] arr){
for (int i = 0; i < arr.length - 1; i++) {
for(int j = 0; j < arr.length - 1 - i; j++){
if(arr[j] > arr[j + 1]){
int temp = arr[j + 1];
arr[j + 1] = arr[j];
arr[j] = temp;
}
}
}
return arr;
}
}public class SelectionSort {
public static void main(String[] args) {
int[] arr = {3, 4, 2, 9, 10, 15, 11, 0, 1};
System.out.println(Arrays.toString(selectionSort(arr)));
}
public static int[] selectionSort(int[] arr){
for (int i = 0; i < arr.length - 1; i++) {
int minIndex = i;
for (int j = i + 1; j < arr.length; j++) {
if(arr[minIndex] > arr[j]){
minIndex = j;
}
}
//交换
int temp = arr[minIndex];
arr[minIndex] = arr[i];
arr[i] = temp;
}
return arr;
}
}public class InsertionSort {
public static void main(String[] args) {
int[] arr = {3, 4, 2, 9, 10, 15, 11, 0, 1};
System.out.println(Arrays.toString(insertionSort(arr)));
}
public static int[] insertionSort(int[] arr) {
int current, preIndex;
for (int i = 1; i < arr.length; i++) {
current = arr[i];
preIndex = i - 1;
while(preIndex >= 0 && current < arr[preIndex]){
arr[preIndex + 1] = arr[preIndex];
preIndex --;
}
arr[preIndex + 1] = current;
}
return arr;
}
}public class ShellSort {
public static void main(String[] args) {
int[] arr = {80, 30, 60, 40, 20, 10, 50, 70};
System.out.println(Arrays.toString(shellSort(arr)));
}
public static int[] shellSort(int[] arr){
int len = arr.length;
for (int gap = len / 2; gap > 0; gap /= 2) {//设置步长
for (int i = gap; i < len ; i++) {
int j = i;
int temp = arr[i];
while(j - gap >= 0 && temp < arr[j - gap]){
arr[j] = arr[j - gap];
j -= gap;
}
arr[j] = temp;
}
}
return arr;
}
}public class MergeSort {
public static void main(String[] args) {
int[] arr = {10, 8, 1, 4, 5, 3, 2, 9, 10, 22, 8};
int[] temp = new int[arr.length];
int[] arr2 = mergeSort(arr, 0, arr.length - 1, temp);
System.out.println(Arrays.toString(arr2));
}
/**
* 归并排序
*
* @param arr
* @param left
* @param right
*/
public static int[] mergeSort(int[] arr, int left, int right, int[] temp) {
if (left < right) {
int mid = (left + right) / 2;
//向左分解
mergeSort(arr, left, mid, temp);
//向右分解
mergeSort(arr, mid + 1, right, temp);
//合并
merge(arr, left, mid, right, temp);
}
return arr;
}
/**
* 合并
*
* @param arr 原数组
* @param left 左指针
* @param mid 中指针
* @param right 右指针
* @param temp 中间数组
*/
public static void merge(int[] arr, int left, int mid, int right, int[] temp) {
int i = left, j = mid + 1, k = 0;
//比较数据大小，从小到大放入temp中
while (i <= mid && j <= right) {
if (arr[i] < arr[j]) {
temp[k] = arr[i];
k++;
i++;
} else {
temp[k] = arr[j];
k++;
j++;
}
}
//判断arr中是否有剩余数据
while (i <= mid) {
temp[k] = arr[i];
k++;
i++;
}
while (j <= right) {
temp[k] = arr[j];
k++;
j++;
}
k = 0;
int c = left;
//将排好序的temp赋给arr
while (c <= right) {
arr[c] = temp[k];
k++;
c++;
}
}
}public class QuickSort {
public static void main(String[] args) {
int[] arr = {4, 6, 7, 0, -1, 2, -4};
int[] arr2 = quickSort(arr, 0, arr.length - 1);
System.out.println(Arrays.toString(arr2));
}
private static int[] quickSort(int[] arr, int left, int right) {
int l = left;
int r = right;
int pivot = arr[(l + r) / 2];
int temp;
while(l < r){
while(arr[l] < pivot){
l++;
}
while(arr[r] > pivot){
r--;
}
if(l >= r){
break;
}
//交换
temp = arr[l];
arr[l] = arr[r];
arr[r] = temp;
if(arr[l] == pivot){
r--;
}
if(arr[r] == pivot){
l++;
}
}
if(l == r){
l++;
r--;
}
if(r > left){
quickSort(arr, left, r);
}
if(l < right){
quickSort(arr, l, right);
}
return arr;
}
}public class HeapSort {
public static void main(String[] args) {
int[] arr = {4, 6, 7, 0, -1, 2, -4};
System.out.println(Arrays.toString(heapSort(arr)));
}
public static int[] heapSort(int[] arr) {
//以最后一个非叶子结点构建大顶堆
for (int i = arr.length / 2 - 1; i >= 0; i--) {
adjustHeap(arr, i, arr.length);
}
//此时顶部元素是最大的，交换顶部元素和末端元素
for (int i = arr.length - 1; i > 0; i--) {
swap(arr, 0, i);
//末端元素已经是最大的了，无需考虑排序
adjustHeap(arr, 0, i);
}
return arr;
}
public static void adjustHeap(int[] arr, int i, int len) {
//保存当前结点
int temp = arr[i];
//遍历当前结点的左子结点
for (int k = 2 * i + 1; k < len; k = 2 * k + 1) {
//如果右结点存在 且 右结点比左结点大，指向右结点
if (k + 1 < len && arr[k] < arr[k + 1]) {
k++;
}
//判断当前结点和左（右）结点哪个大
if (temp < arr[k]) {
//交换
swap(arr, k, i);
//交换后，下次遍历以该子结点作为根节点的子树就会受到影响，因此需要重新指定下次的根节点
i = k;
} else {
//不用交换，直接终止循环
break;
}
}
}
public static void swap(int[] arr, int i, int j) {
int temp = arr[i];
arr[i] = arr[j];
arr[j] = temp;
}
}public class CountingSort {
public static void main(String[] args) {
int[] arr = {4, 6, 7, 0, 1, 2, 4, 1, 7};
System.out.println(Arrays.toString(countingSort(arr)));
}
public static int[] countingSort(int[] arr) {
int max = arr[0];
int sortIndex = 0;
//找到最大值
for (int i = 1; i < arr.length; i++) {
if (arr[i] > max) {
max = arr[i];
}
}
int[] bucket = new int[max + 1];
//将待排序数组的值作为新数组的下标，新数组的下标对应的值就是这个数的个数，
// 因此待排序数组不能有负数
for (int i = 0; i < arr.length; i++) {
bucket[arr[i]]++;
}
// System.out.println("新数组："+Arrays.toString(bucket));
//将新数组的值重新赋给待排序数组
for (int i = 0; i < bucket.length; i++) {
while (bucket[i] > 0) {
arr[sortIndex++] = i;
bucket[i]--;
}
}
return arr;
}
}public class BucketSort {
public static void main(String[] args) {
int[] arr = {4, 6, 7, 0, 1, 2, 4, 1, 7};
System.out.println(Arrays.toString(bucketSort(arr)));
}
public static int[] bucketSort(int[] arr) {
int min = arr[0], max= arr[0];
//找到最大值最小值
for (int i = 0; i < arr.length; i++) {
if(arr[i] < min){
min = arr[i];
}
if(arr[i] > max){
max = arr[i];
}
}
int d = max - min;
int bucketCount = d / 5 + 1; //桶的个数
ArrayList<LinkedList<Integer>> bucket = new ArrayList<>();
//初始化
for (int i = 0; i < bucketCount; i++) {
bucket.add(new LinkedList<Integer>());
}
//遍历待排序数组，将数据放入集合中
for (int i = 0; i < arr.length; i++) {
bucket.get((arr[i] - min) / d).add(arr[i] - min);
}
//对每个桶里的元素排序
for (int i = 0; i < bucketCount; i++) {
Collections.sort(bucket.get(i));
}
//将集合的数据放到原数组里
int k = 0;
for (int i = 0; i < bucketCount; i++) {
for (Integer num : bucket.get(i)) {
arr[k++] = num + min;
}
}
return arr;
}
}public class RadixSort {
public static void main(String[] args) {
int[] arr = {3, 4, 2, 9, 10, 15, 11, 0, 1};
System.out.println(Arrays.toString(radixSort(arr)));
}
public static int[] radixSort(int[] arr) {
int max = arr[0], n = arr.length;
//找到最大数
for (int i = 1; i < n; i++) {
if(max < arr[i]){
max = arr[i];
}
}
//判断max是几位数
int num = 1;
while(max / 10 > 0){
num++;
max /= 10;
}
//创建10个桶
ArrayList<LinkedList<Integer>> bucket = new ArrayList<>(10);
//初始化
for (int i = 0; i < 10; i++) {
bucket.add(new LinkedList<>());
}
//遍历原数组，将数据按规则放到桶中
//从个位开始
for (int i = 1; i <= num; i++) {
//按照数据位数的数字放到桶中
for (int j = 0; j < n; j++) {
//获取数字个位、十位....上的数字
int radix = (arr[j] / (int) Math.pow(10, i - 1)) % 10;
bucket.get(radix).add(arr[j]);
}
//将数据放回原数组
int k = 0;
for (int j = 0; j < 10; j++) {
for(int t : bucket.get(j)){
arr[k++] = t;
}
//清空桶的数据
bucket.get(j).clear();
}
}
return arr;
}
}标签：integer math 大小 str main 初始化 判断 turn 最大的
原文地址：https://www.cnblogs.com/songjilong/p/12234856.html
