update

Author: genkimaru

Diff for: README.md

@@ -1,3 +1,9 @@
 ## practice in leetcode
 https://leetcode.cn/studyplan/top-100-liked/
 
+
+| 算法名称 | 算法关键字         | Path |
+|------ |---------------|------ |
+|快速排序| pivot , split , recursion |/com/leetcode/recursion/QuickSort.java|
+|寻找第K大的元素| pivot , split |com/leetcode/heap/KthLargest.java|
+ 

Diff for: src/main/java/com/leetcode/heap/HeapSort.java

@@ -0,0 +1,58 @@
+package com.leetcode.heap;
+
+public class HeapSort {
+
+    public void heapSort(int[] arr) {
+        int n = arr.length;
+
+        // Build heap (rearrange array)
+        for (int i = n / 2 - 1; i >= 0; i--)
+            heapify(arr, n, i);
+
+        // One by one extract an element from heap
+        for (int i = n - 1; i > 0; i--) {
+            // Move current root to end
+            int temp = arr[0];
+            arr[0] = arr[i];
+            arr[i] = temp;
+
+            // call max heapify on the reduced heap
+            heapify(arr, i, 0);
+        }
+    }
+
+    void heapify(int arr[], int n, int i) {
+        int largest = i; // Initialize largest as root
+        int l = 2 * i + 1; // left = 2*i + 1
+        int r = 2 * i + 2; // right = 2*i + 2
+
+        // If left child is larger than root
+        if (l < n && arr[l] > arr[largest])
+            largest = l;
+
+        // If right child is larger than largest so far
+        if (r < n && arr[r] > arr[largest])
+            largest = r;
+
+        // If largest is not root
+        if (largest != i) {
+            int swap = arr[i];
+            arr[i] = arr[largest];
+            arr[largest] = swap;
+
+            // Recursively heapify the affected sub-tree
+            heapify(arr, n, largest);
+        }
+    }
+
+    public static void main(String[] args) {
+        int[] arr = {12, 11, 13, 5, 6, 7};
+        HeapSort heapSort = new HeapSort();
+        heapSort.heapSort(arr);
+
+        System.out.println("Sorted array:");
+        for (int i : arr) {
+            System.out.print(i + " ");
+        }
+    }
+}

Diff for: src/main/java/com/leetcode/heap/KthLargest.java

@@ -5,6 +5,7 @@
 
 /**
  *   Kth Largest Element in an Array
+ *
  */
 public class KthLargest {
 

Diff for: src/main/java/com/leetcode/slidingwindow/MinWindow.java

@@ -6,6 +6,18 @@
 public class MinWindow {
 
 
+    /**
+     *   算法介绍：
+     *   设置一个targetmap来存放 目标字符串t的 字符和个数。
+     *   设置左右两个指针，开始都指向s字符数组的左端。
+     *   首先，right指针从左向右移动，直到发现了所有的目标字符，记录一个minlen， minstart。
+     *  关键步骤-A） 此时，right停止，而left开始从左向右移动，直到读到第一个目标字符中的任意一个字符， 比如字符a，停止下来。
+     *  关键步骤-B） 此时，right开始继续走，1）直到读到left读到的那个字符，比如字符a， 停止下来；
+     *          2）如果没有读到该字符，right指针到达了字符串长度，从而停止循环，返回结果；
+     *   若1）继续执行关键步骤A->关键步骤B，直到退出循环。
+     *
+     */
+
     public String minWindow(String s, String t) {
             Map<Character, Integer> targetMap = new HashMap<>();
             for (char c : t.toCharArray()) {
@@ -52,8 +64,8 @@ public String minWindow(String s, String t) {
 
     public static void main(String[] args) {
 
-        String str = "ADOBECODEBANC";
-        String substr = "ABC";
+        String str = "axxxxxbcxbxxxxbc";
+        String substr = "abc";
         String s = new MinWindow().minWindow(str, substr);
         System.out.println(s);
 

Diff for: src/main/java/com/leetcode/stack/StackOne.java renamed to src/main/java/com/leetcode/stack/CheckPerentheses.java

@@ -8,7 +8,7 @@
  *
  * using stack data structure
  */
-public class StackOne {
+public class CheckPerentheses {
 
 
     public boolean isValid(String s) {
@@ -31,7 +31,7 @@ public boolean isValid(String s) {
     }
     public static void main(String[] args) {
         String s = "{(abc+bcd)*[cc+dd]}";
-        boolean isvalid = new StackOne().isValid(s);
+        boolean isvalid = new CheckPerentheses().isValid(s);
         System.out.println(isvalid);
     }
 }