基数排序

src/RadixSort.java

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+/**
+ * 基数排序
+ */
+public class RadixSort {
+    private static int getMax(int[] a ){
+        int max = a[0];
+        for (int i : a){
+            if (i > max){
+                max = i;
+            }
+        }
+        return max;
+    }
+    private static void countSort(int[] a, int exp){
+        int[] output = new int[a.length];
+        int[] buckets = new int[10];
+        for (int anA : a) {
+            buckets[(anA / exp) % 10]++;
+        }
+        for (int i : buckets)
+            System.out.print(i + " ");
+        System.out.println();
+        for (int i = 1; i < 10; i++){
+            buckets[i] += buckets[i - 1];
+        }
+        for (int i : buckets)
+            System.out.print(i + " ");
+        System.out.println();
+        for (int i = a.length - 1; i >= 0; i--){
+            output[buckets[(a[i] / exp) % 10] - 1] = a[i];
+            buckets[(a[i] / exp) % 10]--;
+        }
+        for (int i = 0; i < a.length; i++){
+            a[i] = output[i];
+        }
+        output = null;
+        buckets = null;
+    }
+    private static void radixSort(int[] a){
+        int max = getMax(a);
+        for (int exp = 1; max / exp > 0; exp *= 10){
+            countSort(a, exp);
+        }
+    }
+    public static void main(String[] args){
+        int[] a = {53, 3, 542, 748, 14, 214, 154, 63, 616};
+        radixSort(a);
+        for (int i : a){
+            System.out.print(i + " ");
+        }
+    }
+}