/**
* 基数排序
* <ul>
* <li>平均情况:O(d(r+n))</li>
* <li>最好情况:O(d(rd+n))</li>
* <li>最坏情况:O(d(r+n))</li>
* <li>辅助存储:O(d(rd+n))</li>
* <li>稳定</li>
* <ul>
*
* @timestamp Mar 13, 2016 8:59:32 PM
* @author smallbug
*/
public class RadixSort {
public static void main(String[] args) {
int[] data = DataUtil.getData(100000);
// System.out.println(Arrays.toString(data));
long time = System.currentTimeMillis();
data = radixSort(data);
// System.out.println(Arrays.toString(data));
System.out.println("speed " + (System.currentTimeMillis() - time) + " ms");
System.out.println("排序是否成功:" + (DataUtil.verify(data, DataUtil.ASC) ? "是" : "否"));
}
private static int[] radixSort(int[] data) {
int length = String.valueOf(data.length).toCharArray().length;
for (int i = 1; i < length; i++) {
int carve = (int) Math.pow(10, i);// 从个位开始比,然后十位,百位。。。
data = bucketSort(data, carve);
}
return data;
}
private static int[] bucketSort(int[] data, int carve) {
int[] count = new int[10];// 计数数组
int[] result = new int[data.length];// 结果数组
for (int i = 0; i < data.length; i++) {
count[(data[i] % carve) / (carve / 10)]++;// 建立计数表
}
for (int i = 1; i < count.length; i++) {
count[i] = count[i] + count[i - 1];// 格式化计数表
}
for (int i = data.length - 1; i >= 0; i--) {
result[--count[(data[i] % carve) / (carve / 10)]] = data[i];// 根据计数表排序
}
return result;
}
}