738

968

src/main/java/cn/whaifree/leetCode/Greedy/LeetCode738.java

@@ -0,0 +1,65 @@
+package cn.whaifree.leetCode.Greedy;
+
+import org.junit.Test;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/3/6 15:24
+ * @注释
+ */
+public class LeetCode738 {
+
+    @Test
+    public void test() {
+        System.out.println(new Solution().monotoneIncreasingDigits(65832));
+    }
+
+
+    class Solution {
+
+        /**
+         * 98，一旦出现strNum[i - 1] > strNum[i]的情况（非单调递增），首先想让strNum[i - 1]减一，strNum[i]赋值9（因为要最大的数，用9一定满足非递减），这样这个整数就是89
+         * @param N
+         * @return
+         */
+        public int monotoneIncreasingDigits(int N) {
+            String[] strings = (N + "").split("");
+
+            int start = strings.length;
+
+            // 出现递减的两个 前一个-1，找到最先递减的的index，index后面全部为9
+            for (int i = strings.length - 1; i > 0; i--) {
+                if (Integer.parseInt(strings[i]) < Integer.parseInt(strings[i - 1])) {
+                    strings[i - 1] = (Integer.parseInt(strings[i - 1]) - 1) + "";
+                    start = i;
+                }
+            }
+
+
+            for (int i = start; i < strings.length; i++) {
+                strings[i] = "9";
+            }
+            return Integer.parseInt(String.join("",strings));
+        }
+    }
+
+    class Solution1 {
+        public int monotoneIncreasingDigits(int n) {
+            String s = String.valueOf(n);
+            char[] chars = s.toCharArray();
+            int start = s.length();
+            for (int i = s.length() - 2; i >= 0; i--) {
+                if (chars[i] > chars[i + 1]) {
+                    chars[i]--;
+                    start = i+1;
+                }
+            }
+            for (int i = start; i < s.length(); i++) {
+                chars[i] = '9';
+            }
+            return Integer.parseInt(String.valueOf(chars));
+        }
+    }
+
+}

src/main/java/cn/whaifree/leetCode/Greedy/LeetCode968.java

@@ -0,0 +1,66 @@
+package cn.whaifree.leetCode.Greedy;
+
+import cn.whaifree.leetCode.model.TreeNode;
+import org.junit.Test;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/3/6 16:34
+ * @注释
+ */
+public class LeetCode968 {
+
+    @Test
+    public void test() {
+        System.out.println(new Solution().minCameraCover(TreeNode.constructTreeByArray(1, 2, null, 2, 4, 6)));
+    }
+
+
+    /**
+     * 我们分别有三个数字来表示：
+     *
+     * 0：该节点无覆盖
+     * 1：本节点有摄像头
+     * 2：本节点有覆盖
+     */
+    class Solution {
+
+        int res = 0;
+        public int minCameraCover(TreeNode root) {
+
+            // 根节点
+            if (travel(root) == 0) {
+                res++;
+            }
+            return res;
+        }
+
+        public int travel(TreeNode root) {
+
+            if (root == null) {
+                return 2;
+            }
+
+
+            int left = travel(root.left);
+            int right = travel(root.right);
+
+            // 左右节点都有覆盖
+            if (left == 2 && right == 2) return 0;
+
+            //左或右无覆盖，本节点要增加摄像头
+            if (left == 0 || right == 0) {
+                res++;
+                return 1;
+            }
+
+            // 左或右有摄像头，本节点被覆盖
+            if (left == 1 || right == 1) {
+                return 2;
+            }
+
+            return -1;
+        }
+    }
+}

src/main/java/cn/whaifree/leetCode/LeetCode002.java

@@ -1,5 +1,7 @@
 package cn.whaifree.leetCode;
 
+import java.util.ArrayList;
+
 /**
  *
  *
@@ -114,3 +116,25 @@ class ListNode {
     ListNode(int val) { this.val = val; }
     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
 }
+
+class RefCountGC{
+    // 这个成员属性的唯一作用就是占用一点内存
+    private byte[] bigSize = new byte[5*1024*1024];
+    // 引用
+    Object reference = null;
+
+    byte[]buffer = new byte[1*1024*1024];//1MB
+    public static void main(String[] args) {
+        ArrayList<RefCountGC> list = new ArrayList<>();
+        int count = 0;
+        try {
+            while (true) {
+                list.add(new RefCountGC());
+                count++;
+            }
+        }catch(Throwable e){
+            System.out.println("count：" + count);
+            e.printStackTrace();
+        }
+    }
+}