feat(leetcodes): 添加LR181和LeetCode215题目解决方案

- 实现LR181字符串反转逻辑，通过调整空格位置反转单词顺序。
- 添加LeetCode215，采用堆排序算法查找第k大的数字，包含优化的小顶堆实现。- 扩展TreeNode类以支持通过整数数组构建二叉树的功能。

src/main/java/cn/whaifree/leetCode/Array/LeetCode215.java

@@ -0,0 +1,102 @@
+package cn.whaifree.leetCode.Array;
+
+import cn.whaifree.leetCode.model.TreeNode;
+import org.junit.Test;
+
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.PriorityQueue;
+
+public class LeetCode215 {
+
+    @Test
+    public void main()
+    {
+        int[] nums = {3,2,1,5,6,4};
+        int k = 2;
+        Solution solution = new Solution();
+        int i = solution.findKthLargest(nums, k);
+        System.out.println(i);
+    }
+
+    class Solution {
+        public int findKthLargest(int[] nums, int k) {
+
+
+            // 小顶堆
+            PriorityQueue<Integer> priorityQueue = new PriorityQueue<>(new Comparator<Integer>() {
+                @Override
+                public int compare(Integer o1, Integer o2) {
+                    return o1 - o2;
+                }
+            });
+            for (int num : nums) {
+                priorityQueue.offer(num);
+                if (priorityQueue.size() > k) {
+                    priorityQueue.poll();
+                }
+            }
+
+            return priorityQueue.poll();
+        }
+    }
+
+    @Test
+    public void test()
+    {
+        int[] nums = {3,2,1,5,6,4};
+        sort(nums);
+    }
+
+    /**
+     * 所有非叶子节点x（自 n/2 开始，表示下面都是叶子节点）找到子节点中的最大值，如果比x 还大，swap。再排序下一个非叶子节点
+     */
+    public void sort(int[] nums) {
+        sort(nums, nums.length - 1);
+        System.out.println(Arrays.toString(nums));
+    }
+
+    public void sort(int[] nums, int end) {
+        if (end < 0) {
+            return;
+        }
+
+        int nonLeaf = (end) / 2;
+        while (nonLeaf >= 0) {
+
+            TreeNode.constructTreeByArrayWithInteger(nums).printTree();
+            int left = 2 * nonLeaf + 1;
+            int right = 2 * nonLeaf + 2;
+
+            if (left <= end &&right <= end) {
+                if (nums[left] < nums[right]) {
+                    if (nums[right] > nums[nonLeaf]) {
+                        swap(nums, nonLeaf, right);
+                    }
+                }else {
+                    if (nums[left] > nums[nonLeaf]) {
+                        swap(nums, nonLeaf, left);
+                    }
+                }
+            } else if (left <= end) {
+                if (nums[left] < nums[right]) {
+                    if (nums[right] > nums[nonLeaf]) {
+                        swap(nums, nonLeaf, right);
+                    }
+                }
+            }else if (right <= end){
+
+            }
+
+            nonLeaf--;
+        }
+        swap(nums, 0, end);
+        sort(nums, end - 1);
+    }
+
+    public void swap(int[] nums, int start, int end) {
+        int temp = nums[start];
+        nums[start] = nums[end];
+        nums[end] = temp;
+    }
+}

src/main/java/cn/whaifree/leetCode/String/LCR181.java

@@ -0,0 +1,46 @@
+package cn.whaifree.leetCode.String;
+
+import org.junit.Test;
+
+public class LCR181 {
+
+
+    @Test
+    public void main()
+    {
+        Solution solution = new Solution();
+        String s = solution.reverseMessage(" abx  ");
+        System.out.println(s);
+    }
+
+    class Solution {
+        public String reverseMessage(String message) {
+            String trim = message.trim();
+            String[] split = trim.split("\s+");
+            reverse(split);
+            StringBuilder stringBuilder = new StringBuilder();
+            for (String s : split) {
+                if (s.isEmpty()) {
+                    continue;
+                }
+                stringBuilder.append(s).append(" ");
+            }
+            if (!stringBuilder.isEmpty()) stringBuilder.deleteCharAt(stringBuilder.length() - 1);
+            return stringBuilder.toString();
+        }
+
+        public void reverse(String[] strings) {
+            int start = 0;
+            int end = strings.length - 1;
+            while (start < end) {
+                swap(strings, start++, end--);
+            }
+        }
+
+        public void swap(String[] strings, int start, int end) {
+            String temp = strings[start];
+            strings[start] = strings[end];
+            strings[end] = temp;
+        }
+    }
+}

src/main/java/cn/whaifree/leetCode/model/TreeNode.java

@@ -1,6 +1,7 @@
 package cn.whaifree.leetCode.model;
 
 import java.util.*;
+import java.util.function.IntFunction;
 
 /**
  * @version 1.0
@@ -187,6 +188,21 @@ public class TreeNode {
         return constructTree(is);
     }
 
+    public static TreeNode constructTreeByArrayWithInteger(int... s) {
+        ArrayList<Integer> ints = new ArrayList<>();
+        for (Integer integer : s) {
+            ints.add(integer);
+        }
+
+        Integer[] array = ints.toArray(new IntFunction<Integer[]>() {
+            @Override
+            public Integer[] apply(int value) {
+                return new Integer[0];
+            }
+        });
+        return constructTree(array);
+    }
+
     public static TreeNode constructTree(Integer[] array) {
         if (array == null || array.length == 0 || array[0] == null) {
             return null;