diff --git a/notes/算法.md b/notes/算法.md
index d2a1c63f..0b99eb7f 100644
--- a/notes/算法.md
+++ b/notes/算法.md
@@ -1,5 +1,4 @@
 <!-- GFM-TOC -->
-* [一、前言](#一前言)
 * [二、算法分析](#二算法分析)
     * [数学模型](#数学模型)
     * [ThreeSum](#threesum)
@@ -35,7 +34,7 @@
 <!-- GFM-TOC -->
 
 
-# 一、前言
+ # 一、前言
 
 本文实现代码以及测试代码放在 [Algorithm](https://github.com/CyC2018/Algorithm)
 
@@ -1073,30 +1072,37 @@ public T delMax() {
 <div align="center"> <img src="../pics//1f039a45-6b91-4f31-a2c2-6c63eb8bdb56.png" width="300"/> </div><br>
 
 ```java
-public class HeapSort {
-    public static void sort(Comparable[] a) {
-        int N = a.length - 1;
-        for (int k = N / 2; k >= 0; k--)
-            sink(a, k, N);
+public class HeapSort<T extends Comparable<T>> extends Sort<T> {
+    /**
+     * 数组第 0 个位置不能有元素
+     */
+    @Override
+    public void sort(T[] nums) {
+        int N = nums.length - 1;
+        for (int k = N / 2; k >= 1; k--)
+            sink(nums, k, N);
 
         while (N > 1) {
-            swap(a, 1, N--);
-            sink(a, 1, N);
+            swap(nums, 1, N--);
+            sink(nums, 1, N);
         }
     }
 
-
-    private static void sink(Comparable[] a, int k, int N) {
+    private void sink(T[] nums, int k, int N) {
         while (2 * k <= N) {
             int j = 2 * k;
-            if (j < N && less(a, j, j + 1))
+            if (j < N && less(nums, j, j + 1))
                 j++;
-            if (!less(a, k, j))
+            if (!less(nums, k, j))
                 break;
-            swap(a, k, j);
+            swap(nums, k, j);
             k = j;
         }
     }
+
+    private boolean less(T[] nums, int i, int j) {
+        return nums[i].compareTo(nums[j]) < 0;
+    }
 }
 ```