Add 基数排序算法

Author: YSGStudyHards

DotNetGuidePractice/HelloDotNetGuide/Program.cs

@@ -11,6 +11,7 @@ static void Main(string[] args)
 
             #region 常见算法
 
+            //基数排序算法.RadixSortRun();
             //桶排序算法.BucketSortRun();
             //计数排序算法.CountingSortRun();
             //堆排序算法.HeapSortRun();

DotNetGuidePractice/HelloDotNetGuide/常见算法/基数排序算法.cs

@@ -1,13 +1,78 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-
-namespace HelloDotNetGuide.常见算法
+namespace HelloDotNetGuide.常见算法
 {
     public class 基数排序算法
     {
+        public static void RadixSort(int[] array)
+        {
+            if (array == null || array.Length < 2)
+            {
+                return;
+            }
+
+            //获取数组中的最大值，确定排序的位数
+            int max = GetMaxValue(array);
+
+            //进行基数排序
+            for (int exp = 1; max / exp > 0; exp *= 10)
+            {
+                CountingSort(array, exp);
+            }
+        }
+
+        private static void CountingSort(int[] array, int exp)
+        {
+            int arrayLength = array.Length;
+            int[] output = new int[arrayLength];
+            int[] count = new int[10];
+
+            //统计每个桶中的元素个数
+            for (int i = 0; i < arrayLength; i++)
+            {
+                count[(array[i] / exp) % 10]++;
+            }
+
+            //计算每个桶中最后一个元素的位置
+            for (int i = 1; i < 10; i++)
+            {
+                count[i] += count[i - 1];
+            }
+
+            //从原数组中取出元素，放入到输出数组中
+            for (int i = arrayLength - 1; i >= 0; i--)
+            {
+                output[count[(array[i] / exp) % 10] - 1] = array[i];
+                count[(array[i] / exp) % 10]--;
+            }
+
+            //将输出数组复制回原数组
+            for (int i = 0; i < arrayLength; i++)
+            {
+                array[i] = output[i];
+            }
+        }
+
+        private static int GetMaxValue(int[] arr)
+        {
+            int max = arr[0];
+            for (int i = 1; i < arr.Length; i++)
+            {
+                if (arr[i] > max)
+                {
+                    max = arr[i];
+                }
+            }
+            return max;
+        }
+
+        public static void RadixSortRun()
+        {
+            int[] array = { 19, 27, 46, 48, 99, 888, 50, 2, 4, 44, 47, 36, 38, 15, 26, 5, 3 };
+
+            Console.WriteLine("排序前数组：" + string.Join(", ", array));
+
+            RadixSort(array);
 
+            Console.WriteLine("排序后数组：" + string.Join(", ", array));
+        }
     }
 }

DotNetGuidePractice/HelloDotNetGuide/常见算法/桶排序算法.cs

@@ -55,7 +55,7 @@ public static void BucketSort(int[] array)
 
         public static void BucketSortRun()
         {
-            int[] array = { 19, 27, 46, 48, 50, 2, 4, 44, 47, 36, 38, 15, 26, 5, 3, 99, 888, 0, -1 };
+            int[] array = { 19, 27, 46, 48, 50, 2, 4, 44, 47, 36, 38, 15, 26, 5, 3, 99, 888 };
 
             Console.WriteLine("排序前数组：" + string.Join(", ", array));
 

DotNetGuidePractice/HelloDotNetGuide/常见算法/计数排序算法.cs

@@ -52,7 +52,7 @@ public static void CountingSort(int[] array)
 
         public static void CountingSortRun()
         {
-            int[] array = { 19, 27, 46, 48, 50, 2, 4, 44, 47, 36, 38, 15, 26, 5, 3, 99, 888, 0, -1 };
+            int[] array = { 19, 27, 46, 48, 50, 2, 4, 44, 47, 36, 38, 15, 26, 5, 3, 99, 888 };
 
             Console.WriteLine("排序前数组：" + string.Join(", ", array));