本文小編為大家詳細介紹“Java常見排序算法怎么實現”，內容詳細，步驟清晰，細節處理妥當，希望這篇“Java常見排序算法怎么實現”文章能幫助大家解決疑惑，下面跟著小編的思路慢慢深入，一起來學習新知識吧。
匯總：
每輪循環確定最值；
public void bubbleSort(int[] nums){
int temp;
boolean isSort = false; //優化，發現排序好就退出
for (int i = 0; i < nums.length-1; i++) {
for (int j = 0; j < nums.length-1-i; j++) { //每次排序后能確定較大值
if(nums[j] > nums[j+1]){
isSort = true;
temp = nums[j];
nums[j] = nums[j+1];
nums[j+1] = temp;
}
}
if(!isSort){
return;
} else {
isSort = false;
}
}
}每次選出最值，再交換到邊上；
public void selectSort(int[] nums){
for (int i = 0; i < nums.length-1; i++) {
int index = i;
int minNum = nums[i];
for (int j = i+1; j < nums.length; j++) {
if(nums[j] < minNum){
minNum = nums[j];
index = j;
}
}
if(index != i){
nums[index] = nums[i];
nums[i] = minNum;
}
}
}對循環的每個數找到屬于自己的位置插入；
public void insertionSort(int[] nums){
for (int i = 1; i < nums.length; i++) {
int j = i;
int insertNum = nums[i];
while(j-1 >= 0 && nums[j-1] > insertNum){
nums[j] = nums[j-1];
j--;
}
nums[j] = insertNum;
}
}選一個基本值，小于它的放一邊，大于它的放另一邊；
public void quickSortDfs(int[] nums, int left, int right){
if(left > right){
return;
}
int l = left;
int r = right;
int baseNum = nums[left];
while(l < r){
//必須右邊先走
while(nums[r] >= baseNum && l < r){
r--;
}
while(nums[l] <= baseNum && l < r){
l++;
}
int temp = nums[l];
nums[l] = nums[r];
nums[r] = temp;
}
nums[left] = nums[l];
nums[l] = baseNum;
quickSortDfs(nums, left, r-1);
quickSortDfs(nums, l+1, right);
}分治算法；
//歸
public void mergeSortDfs(int[] nums, int l, int r){
if(l >= r){
return;
}
int m = (l+r)/2;
mergeSortDfs(nums, l, m);
mergeSortDfs(nums, m+1, r);
merge(nums, l, m, r);
}
//并
private void merge(int[] nums, int left, int mid, int right){
int[] temp = new int[right-left+1];
int l = left;
int m = mid+1;
int i = 0;
while(l <= mid && m <= right){
if(nums[l] < nums[m]){
temp[i++] = nums[l++];
} else {
temp[i++] = nums[m++];
}
}
while(l <= mid){
temp[i++] = nums[l++];
}
while(m <= right){
temp[i++] = nums[m++];
}
System.arraycopy(temp, 0, nums, left, temp.length);
}引入步長減少數字交換次數提高效率；
public void shellBubbleSort(int[] nums){
for (int step = nums.length/2; step > 0 ; step /= 2) {
for (int i = step; i < nums.length; i++) {
for (int j = i-step; j >= 0; j -= step) {
if(nums[j] > nums[j+step]){
int temp = nums[j];
nums[j] = nums[j+step];
nums[j+step] = temp;
}
}
}
}
}public void shellInsertSort(int[] nums){
for (int step = nums.length/2; step > 0; step /= 2) {
for (int i = step; i < nums.length; i++) {
int j = i;
int insertNum = nums[i];
while(j-step >= 0 && nums[j-step] > insertNum){
nums[j] = nums[j-step];
j-=step;
}
nums[j] = insertNum;
}
}
}大頂堆實現升序，每次將最大值移到堆的最后一個位置上；
public void heapSort2(int[] nums) {
for(int i = nums.length/2-1; i >= 0; i--){
sift(nums, i, nums.length);
}
for (int i = nums.length-1; i > 0; i--) {
int temp = nums[0];
nums[0] = nums[i];
nums[i] = temp;
sift(nums, 0, i);
}
}
private void sift(int[] nums, int parent, int len) {
int value = nums[parent];
for (int child = 2*parent +1; child < len; child = child*2 +1) {
if(child+1 < len && nums[child+1] > nums[child]){
child++;
}
if(nums[child] > value){
nums[parent] = nums[child];
parent = child;
} else {
break;
}
}
nums[parent] = value;
}按順序統計每個數出現次數；
public void countSort(int[] nums){
int max = Integer.MIN_VALUE;
int min = Integer.MAX_VALUE;
for(int num : nums){
max = Math.max(max, num);
min = Math.min(min, num);
}
int[] countMap = new int[max-min+1];
for(int num : nums){
countMap[num-min]++;
}
int i = 0;
int j = 0;
while(i < nums.length && j < countMap.length){
if(countMap[j] > 0){
nums[i] = j+min;
i++;
countMap[j]--;
} else {
j++;
}
}
}類似計數排序，不同點在于統計的是某個區間（桶）里的數；
public void bucketSort(int[] nums){
int max = Integer.MIN_VALUE;
int min = Integer.MAX_VALUE;
for(int num : nums){
max = Math.max(max, num);
min = Math.min(min, num);
}
int bucketCount = (max-min)/nums.length+1;
List<List<Integer>> bucketList = new ArrayList<>();
for (int i = 0; i < bucketCount; i++) {
bucketList.add(new ArrayList<>());
}
for(int num : nums){
int index = (num-min)/nums.length;
bucketList.get(index).add(num);
}
for(List<Integer> bucket : bucketList){
Collections.sort(bucket);
}
int j = 0;
for(List<Integer> bucket : bucketList){
for(int num : bucket){
nums[j] = num;
j++;
}
}
}按個、十、百位依次歸類排序；
public void radixSort(int[] nums){
int min = Integer.MAX_VALUE;
int max = Integer.MIN_VALUE;
for (int num : nums) {
min = Math.min(min, num);
max = Math.max(max, num);
}
for (int i = 0; i < nums.length; i++) {
nums[i] -= min;
}
max -= min;
int maxLen = (max+"").length();
int[][] bucket = new int[nums.length][10];
int[] bucketCount = new int[10];
for (int i = 0, n = 1; i < maxLen; i++, n*=10) {
for (int num : nums) {
int digitVal = num / n % 10;
bucket[bucketCount[digitVal]][digitVal] = num;
bucketCount[digitVal]++;
}
int index = 0;
for (int j = 0; j < bucketCount.length; j++) {
if(bucketCount[j] > 0){
for (int k = 0; k < bucketCount[j]; k++) {
nums[index] = bucket[k][j];
index++;
}
}
bucketCount[j] = 0;
}
}
for (int i = 0; i < nums.length; i++) {
nums[i] += min;
}
}public void priorityQueueSort(int[] nums){
PriorityQueue<Integer> queue = new PriorityQueue<>();
for(int num : nums){
queue.offer(num);
}
for (int i = 0; i < nums.length; i++) {
nums[i] = queue.poll();
}
}public void arraysApiSort(int[] nums){
Arrays.sort(nums);
}讀到這里，這篇“Java常見排序算法怎么實現”文章已經介紹完畢，想要掌握這篇文章的知識點還需要大家自己動手實踐使用過才能領會，如果想了解更多相關內容的文章，歡迎關注億速云行業資訊頻道。
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