2025-01-18 基数排序

src/dataANDcalc/java/SortAlgori/RadixSort.java

@@ -0,0 +1,71 @@
+package SortAlgori;
+
+public class RadixSort {
+
+    private int[][] bucket;
+
+    private int[] arr;
+
+    // 用来记录每个桶的有效数量
+    private int[] bucketCounts;
+
+    public RadixSort(int[] arr){
+//        this.arr = new int[]{53,3,542,748,14,214};
+        this.arr = arr;
+        this.bucket = new int[10][arr.length];
+        this.bucketCounts = new int[10];
+    }
+
+    private void sort(){
+        int digit = 1;
+        while(true){
+            // 先从最低位数开始进行桶排序，然后十位、百位...
+            for(int i=0; i<arr.length; i++){
+                int temp = (arr[i]/digit) % 10;
+                bucket[temp][bucketCounts[temp]] = arr[i];
+                bucketCounts[temp] ++;
+            }
+            //当所有的数字排完后，如果第0个桶的长度等于数组长度，即已经排完了
+            if(bucketCounts[0] == arr.length){
+                break;
+            }
+
+            //从各个桶中取出元素回到原始队列中
+            int index = 0;
+            for(int i=0; i<10; i++){
+                if(bucketCounts[i] > 0){
+                    for(int j=0; j<bucketCounts[i]; j++){
+                        arr[index] = bucket[i][j];
+                        index ++;
+                    }
+                }
+                bucketCounts[i] = 0;
+            }
+            //取完后位数对位数*10,已作下一次排序
+            digit *= 10;
+        }
+    }
+
+    public void show(){
+        for (int i = 0; i < arr.length; i++) {
+            System.out.print(arr[i] + " ");
+        }
+        System.out.println();
+    }
+
+    public static void main(String[] args) {
+        int[] arr = new int[80000];
+        System.out.println("排序前的序列：");
+        for(int i=0; i<80000; i++){
+            arr[i] = (int)(Math.random()*100000);
+            System.out.print(arr[i] + " ");
+        }
+        RadixSort radixSort = new RadixSort(arr);
+        long startTime = System.currentTimeMillis();
+        radixSort.sort();
+        long endTime = System.currentTimeMillis();
+        System.out.println("排序后的序列：");
+        radixSort.show();
+        System.out.println("排序所花费的时间：" + (endTime - startTime) + "ms");
+    }
+}