Bubble sorting method : Records with smaller keywords are like bubbles floating up one after another, and records with larger keywords are like stones sinking, and one of the largest stones sinks to the bottom in each trip.
The essence of the algorithm: (the maximum value is the key point, it must be put to the end, so the loop is like this) Every time, the comparison is made from the first position to the bottom, the minimum value rises once, and the last bit advances (i.e. The last digit has just been determined by the maximum value no longer participate in the comparison, the number of comparisons is reduced by 1)
Complexity: Time complexity O(n2), space complexity O(1)
JAVA source code (successfully run, Date class is required)
The code copy is as follows:
public static void bubbleSort(Date[] days) {
int len = days.length;
Date temp;
for (int i = len - 1; i >= 1; i--) {
for (int j = 0; j < i; j++) {
if (days[j].compare(days[j + 1]) > 0) {
temp = days[j + 1];
days[j + 1] = days[j];
days[j] = temp;
}
}
}
}
class Date {
int year, month, day;
Date(int y, int m, int d) {
year = y;
month = m;
day = d;
}
public int compare(Date date) {
return year > date.year ? 1 : year < date.year ? -1
: month > date.month ? 1 : month < date.month ? -1
: day > date.day ? 1 : day < date.day ? -1 : 0;
}
public void print() {
System.out.println(year + " " + month + " " + day);
}
}
The code copy is as follows:
package testSortAlgorithm;
public class BubbleSort {
public static void main(String[] args) {
int array[] = { 5, 6, 8, 4, 2, 4, 9, 0 };
bubbleSort(array);
for (int i = 0; i < array.length; i++) {
System.out.println(array[i]);
}
}
public static void bubbleSort(int array[]) {
int temp;
for (int i = array.length - 1; i > 0; i--) {
for (int j = 0; j < i; j++) {
if (array[j] > array[j + 1]) {
temp = array[j];
array[j] = array[j + 1];
array[j + 1] = temp;
}
}
}
}
}