wen 计数排序
![计数排序
[编程语言教程]](https://www.zixueka.com/wp-content/uploads/2024/01/1706709805-f31953812ec3289.jpg)
import java.util.Arrays;
import java.util.Random;
public class CountSort {
static class Item {
int index;
int num;
}
private static void sort(Item[] items, int bound) {
int n = items.length;
int[] count = new int[bound];
int[] sum = new int[bound];
Item[] cache = Arrays.copyOf(items, n);
for (int i = 0; i < n; ++ i) {
count[items[i].num] ++;
}
sum[0] = count[0];
for (int i = 1; i < bound; ++ i) {
sum[i] = sum[i - 1] + count[i];
}
for (int i = n - 1; i >= 0; -- i) {
items[-- sum[cache[i].num]] = cache[i];
}
}
public static void main(String[] args) {
int n = 10;
Random random = new Random();
Item[] items = new Item[n];
for (int i = 0; i < n; ++ i) {
items[i] = new Item();
items[i].index = i;
items[i].num = random.nextInt(5);
}
Arrays.stream(items).forEach(item -> {
System.out.println(item.index + "->" + item.num);
});
sort(items, 5);
System.out.println("排序后");
Arrays.stream(items).forEach(item -> {
System.out.println(item.index + "->" + item.num);
});
}
}
计数排序
原文地址：https://blog.51cto.com/tianyiya/2553857
