添加希尔排序

sort/shellsort/main.cpp

@@ -0,0 +1,67 @@
+//
+// Created by tangs on 2018/11/18.
+//
+
+#include <iostream>
+
+using namespace std;
+
+// 抄书的算法;
+// 希尔排序的时间复杂度涉及到一个未解决的数学难题，当n在某个范围内时，可以达到O(n^1.3).
+// 最坏的时候为O(n^2).
+void ShellSort(int A[], int n) {
+    int dk, i, j;
+    for (dk = n / 2; dk >= 1; dk /= 2) {
+        for (i = dk ; i < n; i++) {
+            if (A[i] < A[i - dk]) {
+                A[0] = A[i];
+                for (j = i - dk; j > 0 && A[0] < A[j]; j -= dk) {
+                    A[j + dk] = A[j];
+                }
+                A[j + dk] = A[0];
+            }
+        }
+    }
+}
+
+void ShellSortBySelf(int A[], int n) {
+    int dk, i, j;
+    int temp;
+    for (dk = n / 2; dk >= 1; dk /= 2) {
+        for (i = dk; i < n; i++) {
+            if (A[i] < A[i - dk]) {
+                temp = A[i];
+                for (j = i-dk; j >= 0 && A[j]>temp; j -= dk) {
+                    A[j + dk] = A[j];
+                }
+                A[j + dk] = temp;
+            }
+        }
+    }
+}
+
+int main(){
+    int A1[] = {6, 1, 5, 2, 1, 9, 10, 24, 7, 0};
+    ShellSort(A1, 10);
+
+    // print:
+    // 0 0 1 1 2 5 7 9 10 24
+    for (int i = 0; i < 10; i++) {
+        cout << A1[i] << " ";
+    }
+    cout << endl;
+
+    // --------------------------------------------------------------------------
+
+    int A2[] = {6, 1, 5, 2, 1, 9, 10, 24, 7, 0};
+    ShellSortBySelf(A2, 10);
+
+    // print:
+    // 0 1 1 2 5 6 7 9 10 24
+    for (int i = 0; i < 10; i++) {
+        cout << A2[i] << " ";
+    }
+    cout << endl;
+
+    return 0;
+}