+ * dp[i] = 遍历0~i-1，找到dp[k]*dp[i-k]的最大值 + *
+ * 0 1 2 3 4 5 6 7 + * 1 1 2 4 6 9 12 + * + * @param n + * @return + */ + public int integerBreak(int n) { +// if (n == 2) return 1; + int[] dp = new int[n + 1]; + dp[0] = 1; + dp[1] = 1; + for (int i = 2; i <= n; i++) { + int tmpMax = Integer.MIN_VALUE; + for (int j = 1; j < i; j++) { + tmpMax = Math.max(tmpMax, dp[j] * (i - j)); // 7 可能拆成（2 2）3 即dp[4] * 7-4 + tmpMax = Math.max(tmpMax, j * (i - j)); // 4 可能拆成 2 2 即ij 22 + } + dp[i] = tmpMax; + } + return dp[n]; + } + + static Object o = new Object(); + static int count = 0; + + public static void main(String[] args) { + + new Thread(() -> { + for (int i = 0; i < 100; i++) { + synchronized (o) { + while (count % 3 != 1) { + try { + o.wait(); + } catch (InterruptedException e) { + throw new RuntimeException(e); + } + } + System.out.println("a"); + o.notifyAll(); + count++; + } + } + + }).start(); + + + new Thread(() -> { + for (int i = 0; i < 100; i++) { + synchronized (o) { + while (count % 3 != 0) { + try { + o.wait(); + } catch (InterruptedException e) { + throw new RuntimeException(e); + } + } + System.out.println("b"); + o.notifyAll(); + count++; + } + } + + }).start(); + + new Thread(() -> { + for (int i = 0; i < 100; i++) { + synchronized (o) { + while (count % 3 != 2) { + + try { + o.wait(); + } catch (InterruptedException e) { + throw new RuntimeException(e); + } + + } + System.out.println("c"); + o.notifyAll(); + count++; + } + } + + }).start(); + + + } +} diff --git a/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode509.java b/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode509.java new file mode 100644 index 0000000..39d58a5 --- /dev/null +++ b/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode509.java @@ -0,0 +1,30 @@ +package cn.whaifree.redo.redo_all_240721; + +/** + * @version 1.0 + * @Author whai文海 + * @Date 2024/8/10 18:33 + * @注释 + */ +public class LeetCode509 { + + public int fib(int n) { + if (n == 0) { + return 0; + } + if (n == 1) { + return 1; + } + return fib(n - 1) + fib(n - 2); + } + public int fib1(int n) { + + int[] dp = new int[n + 1]; + dp[0] = 0; + dp[1] = 1; + for (int i = 2; i <= n; i++) { + dp[i] = dp[i - 1] + dp[i - 2]; + } + return dp[n]; + } +} diff --git a/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode96.java b/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode96.java new file mode 100644 index 0000000..3c60ff5 --- /dev/null +++ b/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode96.java @@ -0,0 +1,54 @@ +package cn.whaifree.redo.redo_all_240721; + +import org.junit.Test; + +/** + * @version 1.0 + * @Author whai文海 + * @Date 2024/8/10 18:40 + * @注释 + */ +public class LeetCode96 { + + @Test + public void test() { + Solution solution = new Solution(); + int i = solution.numTrees(3); + System.out.println(i); + } + + class Solution { + /** + * 1 1 + * 2 2 + * 节点 + * + * n=4 + * + * 左边三个节点，右边没有 dp[3] + dp[0] + * dp[2] + dp[1] + * dp[1] + dp[2] + * dp[0] + dp[3] + * + * @param n + * @return + */ + public int numTrees(int n) { + if (n <= 2) { + return n; + } + int[] dp = new int[n + 1]; + dp[0] = 1; + dp[1] = 1; + dp[2] = 2; + for (int i = 3; i < dp.length; i++) { + int var = 0; + for (int j = 0; j < i; j++) { + var += (dp[i - j - 1] * dp[j]); + } + dp[i] = var; + } + return dp[n]; + } + } +} diff --git a/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode968.java b/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode968.java new file mode 100644 index 0000000..8093baf --- /dev/null +++ b/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode968.java @@ -0,0 +1,65 @@ +package cn.whaifree.redo.redo_all_240721; + +import cn.whaifree.leetCode.model.TreeNode; +import org.junit.Test; + +/** + * @version 1.0 + * @Author whai文海 + * @Date 2024/8/10 16:52 + * @注释 + */ +public class LeetCode968 { + + @Test + public void test() { + System.out.println(new Solution().minCameraCover(TreeNode.constructTreeByArray(1,2,null,null,3,4,null,null,5,6))); + System.out.println(new Solution().minCameraCover(TreeNode.constructTreeByArray(1,2,null,3,null,4,null,null,5))); + + } + + class Solution { + int res = 0; + /** + * 0 被覆盖 + * 1 有监控 + * 2 没覆盖 + * + * @param root + * @return + */ + public int minCameraCover(TreeNode root) { + if (circle(root) == 2) { + res++; + } + return res; + } + + public int circle(TreeNode root) { + if (root == null) { + return 0; + } + + int left = circle(root.left); + int right = circle(root.right); + + // 左边或者右边有未覆盖的，就在这里安排一个监控 + if (left == 2 || right == 2) { + res++; + return 1; + } + + // 左边和右边有监控，这里就被覆盖了 + if (left == 1 || right == 1) { + return 0; + } + + // 左右都覆盖，这里就没覆盖 + if (left == 0 && right == 0) { + return 2; + } + + return -1; + } + } +}