diff --git a/src/main/java/cn/whaifree/leetCode/Greedy/LeetCode1005.java b/src/main/java/cn/whaifree/leetCode/Greedy/LeetCode1005.java
new file mode 100644
index 0000000..ad4bbba
--- /dev/null
+++ b/src/main/java/cn/whaifree/leetCode/Greedy/LeetCode1005.java
@@ -0,0 +1,113 @@
+package cn.whaifree.leetCode.Greedy;
+
+import org.junit.Test;
+
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.stream.IntStream;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/2/27 11:42
+ * @注释
+ */
+public class LeetCode1005 {
+
+ @Test
+ public void test() {
+ System.out.println(new Solution().largestSumAfterKNegations(new int[]{-2,5,0,2,-2}, 3));
+ System.out.println(new Solution().largestSumAfterKNegations(new int[]{4,2,3}, 1))
+ ;
+
+ System.out.println(new Solution1().largestSumAfterKNegations(new int[]{-2,5,0,2,-2}, 3));
+ System.out.println(new Solution1().largestSumAfterKNegations(new int[]{4,2,3}, 1));
+ }
+
+
+ class Solution {
+
+ /**
+ * 注意几个例子
+ * 1. nums = [3,-1,0,2], k = 3 选择下标 (1, 2, 2) ，nums 变为 [3,1,0,2]
+ *
+ * -2,5,1,2,-2
+ * 按绝对值逆转 5 -2 2 -2 1
+ * 每次遇到负数，变为相反数
+ * // 剩下的k如果是奇数，就把最后一个逆转
+ *
+ * @param nums
+ * @param k
+ * @return
+ */
+ public int largestSumAfterKNegations(int[] nums, int k) {
+ // 按绝对值从大到小排序，对前k个负数进行相反数
+ nums = IntStream.of(nums)
+ .boxed()
+ .sorted((o1, o2) -> Math.abs(o2) - Math.abs(o1))
+ .mapToInt(Integer::intValue).toArray();
+
+
+ for (int i = 0; i < nums.length; i++) {
+ if (k > 0 && nums[i] < 0) {
+ nums[i] = -nums[i];
+ k--;
+ }
+ }
+
+ // 此时还有k个没减去,k为偶数则不管，k为奇数就把最小那个变为正数
+ if (k % 2 == 1) {
+ nums[nums.length-1] = -nums[nums.length-1];
+ }
+
+
+ return Arrays.stream(nums).sum();
+ }
+ }
+
+ class Solution1 {
+
+ /**
+ * 注意几个例子
+ * 1. nums = [3,-1,0,2], k = 3 选择下标 (1, 2, 2) ，nums 变为 [3,1,0,2]
+ *
+ * -2,5,1,2,-2
+ * 排序
+ * -2 -2 1 2 5
+ * 逆转
+ * 2 2 1 2 5
+ * 将最下的数逆转,sum-min-min
+ * 2 2 -1 2 5
+ *
+ * @param nums
+ * @param k
+ * @return
+ */
+ public int largestSumAfterKNegations(int[] nums, int k) {
+ // 按绝对值从大到小排序，对前k个负数进行相反数
+ Arrays.sort(nums);
+
+
+ int sum = 0;
+ int minValue = Integer.MAX_VALUE;
+ for (int i = 0; i < nums.length; i++) {
+ if (k > 0 && nums[i] < 0) {
+ nums[i] = -nums[i];
+ k--;
+ }
+ sum += nums[i];
+ minValue = Math.min(minValue, nums[i]);
+ }
+
+ // 此时还有k个没减去,k为偶数则不管，k为奇数就把最小那个变为正数
+ if (k % 2 == 1) {
+ // 减去在遍历过程中加的minValue部分和通过变换负数的部分
+ return sum - minValue - minValue;
+ }else {
+ return sum;
+ }
+
+ }
+ }
+
+}
diff --git a/src/main/java/cn/whaifree/leetCode/Greedy/LeetCode134.java b/src/main/java/cn/whaifree/leetCode/Greedy/LeetCode134.java
new file mode 100644
index 0000000..09397bb
--- /dev/null
+++ b/src/main/java/cn/whaifree/leetCode/Greedy/LeetCode134.java
@@ -0,0 +1,105 @@
+package cn.whaifree.leetCode.Greedy;
+
+import org.junit.Test;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/2/27 20:02
+ * @注释
+ */
+public class LeetCode134 {
+
+ @Test
+ public void test() {
+ System.out.println(new Solution().canCompleteCircuit(
+ new int[]{5,1,2,3,4},
+ new int[]{4,4,1,5,1}
+ ));
+
+ }
+
+ class Solution {
+ /**
+ *
+ * @param gas 加油站有的油
+ * @param cost 行驶代价
+ * @return
+ */
+ public int canCompleteCircuit(int[] gas, int[] cost) {
+
+ int[] rent = new int[gas.length];
+ int total = 0;
+ for (int i = 0; i < gas.length; i++) {
+ rent[i] = gas[i] - cost[i];
+ total += rent[i];
+ }
+ // 如果全部剩余<0 则必然跑不了一圈
+ if (total < 0) {
+ return -1;
+ }
+
+
+ // 以下为必然可以跑一圈的
+ // 如果当前剩余不够用，则让指针指向i+1
+ int curSum = 0;
+ int index = 0;
+ for (int i = 0; i < rent.length; i++) {
+ curSum += rent[i];
+ if (curSum < 0) {
+ index = (i + 1) % gas.length ;
+ curSum = 0;
+ }
+ }
+ // 1. 前提，必然能跑一圈
+ // 2. 没有进入某个i之后都没有curSum<0 那么就是正确的i
+ return index;
+ }
+
+ }
+// class Solution {
+// /**
+// *
+// * @param gas 加油站有的油
+// * @param cost 行驶代价
+// * @return
+// */
+// public int canCompleteCircuit(int[] gas, int[] cost) {
+// int needSum = 0;
+// for (int i : cost) {
+// needSum += i;
+// }
+//
+// int iHave = 0;
+// int sumAdd = 0;
+// int start = 0;
+// for (int i = 0; i < gas.length; i++) {
+// iHave += gas[i];
+// sumAdd += gas[i];
+// if (iHave < cost[i]) {
+// iHave = 0;
+// i = start;
+// start = start + 1;
+// sumAdd = 0;
+// continue;
+// }
+// iHave -= cost[i];
+// if (sumAdd >= needSum) {
+// return start;
+// }
+//
+// if (i == gas.length - 1) {
+// i = -1;
+// }
+//
+// if (start == gas.length - 1 && start != i) {
+// break;
+// }
+// }
+//
+// return -1;
+// }
+//
+// }
+
+}
diff --git a/src/main/java/cn/whaifree/leetCode/Greedy/LeetCode135.java b/src/main/java/cn/whaifree/leetCode/Greedy/LeetCode135.java
new file mode 100644
index 0000000..32fa45e
--- /dev/null
+++ b/src/main/java/cn/whaifree/leetCode/Greedy/LeetCode135.java
@@ -0,0 +1,63 @@
+package cn.whaifree.leetCode.Greedy;
+
+import org.junit.Test;
+
+import java.util.Arrays;
+import java.util.Vector;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/2/28 12:44
+ * @注释
+ */
+public class LeetCode135 {
+
+ @Test
+ public void tesr() {
+ System.out.println(new Solution().candy(new int[]{1, 2, 2, 5, 4, 3, 2}));
+ }
+
+
+ class Solution {
+ public int candy(int[] ratings) {
+ // 从前往后遍历，遇到ratings[i]>ratings[i-1] score[i]+1
+ int length = ratings.length;
+
+ int[] scores = new int[length];
+ scores[0] = 1;
+
+ for (int i = 1; i < length; i++) {
+ if (ratings[i] > ratings[i - 1]) {
+ scores[i] = scores[i - 1] + 1;
+ }else {
+ scores[i] = 1;
+ }
+ }
+
+ // 从后往前
+ for (int i = length -1; i > 0; i--) {
+ /**
+ * 如果 ratings[i] < ratings[i - 1]，此时candyVec[i-1]（第i-1个小孩的糖果数量）就有两个选择了，
+ * - 一个是candyVec[i] + 1（从右边这个加1得到的糖果数量），
+ * - 一个是candyVec[i-1]（之前比较右孩子大于左孩子得到的糖果数量）。
+ * 如 5 3
+ * 从右边向左边，i-1可选择为 3+1 或者原来的 5，从左往右已经处理过的，
+ * 同时要满足同时保证i小孩既大于左也大于右边，那么取最大值。
+ * 同时保证i小孩既大于左也大于右边
+ */
+ if (ratings[i] < ratings[i - 1]) {
+ scores[i - 1] = Math.max(scores[i] + 1, scores[i - 1]);
+ }
+ }
+
+ int scoreSum = 0;
+ for (int score : scores) {
+ scoreSum += score;
+ }
+
+ return scoreSum;
+ }
+ }
+
+}
diff --git a/src/main/java/cn/whaifree/leetCode/Greedy/LeetCode45.java b/src/main/java/cn/whaifree/leetCode/Greedy/LeetCode45.java
new file mode 100644
index 0000000..04b653d
--- /dev/null
+++ b/src/main/java/cn/whaifree/leetCode/Greedy/LeetCode45.java
@@ -0,0 +1,102 @@
+package cn.whaifree.leetCode.Greedy;
+
+import org.junit.Test;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/2/27 11:01
+ * @注释
+ */
+public class LeetCode45 {
+
+ @Test
+ public void test() {
+ System.out.println(new Solution().jump(new int[]{2,3,1,1,4}));
+ }
+
+ class Solution {
+ /**
+ * 每个区间内只有一个最跳数
+ * 每个区间只增加一次jump
+ * 1. 标记临时最大区间
+ * 2. 标记区间结束时jump++
+ * @param nums
+ * @return
+ */
+ public int jump(int[] nums) {
+
+ // 最远覆盖范围能否到达nums.length-1
+
+ if (nums.length == 1) {
+ return 0;
+ }
+
+ // 最大覆盖范围
+ int maxCover = 0;
+
+ // 当前index覆盖范围区间
+ int curInterval = 0;
+ int jumpCount = 0;
+ for (int i = 0; i < nums.length; i++) {
+ // 当前最大覆盖区间
+ maxCover = Math.max(maxCover, i + nums[i]);
+
+ // 必须等待区间增加后再判断是否到末位
+ if (maxCover >= nums.length - 1) {
+ jumpCount++;
+ break;
+ }
+
+ // 如果到了当前index覆盖的区间最后一个
+ if (i == curInterval) {
+ jumpCount++;
+ curInterval = maxCover;
+
+ }
+
+
+ }
+ return jumpCount;
+ }
+ }
+
+ class Solution1 {
+ /**
+ * 每个区间内只有一个最跳数
+ * 每个区间只增加一次jump
+ * 1. 标记临时最大区间
+ * 2. 到达最大跳数++
+ * @param nums
+ * @return
+ */
+ public int jump(int[] nums) {
+
+ // 最远覆盖范围能否到达nums.length-1
+
+ if (nums.length == 1) {
+ return 0;
+ }
+
+ // 最大覆盖范围
+ int maxCover = 0;
+
+ // 当前index覆盖范围区间
+ int curInterval = 0;
+ int jumpCount = 0;
+ for (int i = 0; i < nums.length - 1; i++) {
+ // if (nextDistance >= nums.size() - 1) break;
+ // 让nums.length变成num.length-1 本质是一样的
+
+ // 当前最大覆盖区间
+ maxCover = Math.max(maxCover, i + nums[i]);
+ if (i == curInterval) {
+ jumpCount++;
+ curInterval = maxCover;
+ }
+ }
+ return jumpCount;
+ }
+ }
+
+}
diff --git a/src/main/java/cn/whaifree/leetCode/Greedy/LeetCode55.java b/src/main/java/cn/whaifree/leetCode/Greedy/LeetCode55.java
new file mode 100644
index 0000000..ce8b71f
--- /dev/null
+++ b/src/main/java/cn/whaifree/leetCode/Greedy/LeetCode55.java
@@ -0,0 +1,75 @@
+package cn.whaifree.leetCode.Greedy;
+
+import cn.whaifree.leetCode.Tree.LeetCode94;
+import org.junit.Test;
+import sun.misc.Launcher;
+
+import java.net.URL;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/2/26 11:33
+ * @注释
+ */
+public class LeetCode55 {
+
+ @Test
+ public void test() {
+ System.out.println(new Solution().canJump(new int[]{2,0,0}));
+
+
+
+ }
+
+
+
+
+
+ class CustomClassLoader extends ClassLoader {
+ public CustomClassLoader(ClassLoader parent) {
+ super(parent);
+ }
+
+ @Override
+ protected Class findClass(String name) throws ClassNotFoundException {
+ byte[] res = getClassFromCustomClass(name);
+ if (res != null) {
+ return defineClass(name, res, 0, res.length);
+ } else {
+ throw new ClassNotFoundException(name);
+ }
+ }
+
+ private byte[] getClassFromCustomClass(String name) {
+ //自定义路径加载指定类
+ // 加密解密
+ return null;
+ }
+ }
+
+ class Solution {
+ /**
+ * 每个index都有一个cover覆盖范围，一旦这个范围可以覆盖nums，就能够返回
+ * @param nums
+ * @return
+ */
+ public boolean canJump(int[] nums) {
+ if (nums.length == 1) {
+ return true;
+ }
+
+ // cover表示最远能到哪里
+ int cover = 0;
+ // 注意这里cover表示能够覆盖的最远范围，不能超过他
+ for (int i = 0; i <= cover; i++) {
+ cover = Math.max(i + nums[i], cover);
+ if (cover >= nums.length - 1) {
+ return true;
+ }
+ }
+ return false;
+ }
+
+ }
+}
diff --git a/src/main/java/cn/whaifree/leetCode/Greedy/LeetCode860.java b/src/main/java/cn/whaifree/leetCode/Greedy/LeetCode860.java
new file mode 100644
index 0000000..9d4c63b
--- /dev/null
+++ b/src/main/java/cn/whaifree/leetCode/Greedy/LeetCode860.java
@@ -0,0 +1,58 @@
+package cn.whaifree.leetCode.Greedy;
+
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/2/28 13:22
+ * @注释
+ */
+public class LeetCode860 {
+
+ @Test
+ public void test() {
+ System.out.println(new Solution().lemonadeChange(new int[]{5,5,10,10,20}));
+ }
+
+ class Solution {
+
+ /**
+ * bills[i] 不是 5 就是 10 或是 20
+ * @param bills
+ * @return
+ */
+ public boolean lemonadeChange(int[] bills) {
+
+ int fiveHave = 0; // 有5元的钞票数
+ int tenHave = 0; // 10元钞票数
+ for (int i = 0; i < bills.length; i++) {
+
+ if (bills[i] == 5) { // 5元直接收下
+ fiveHave++;
+ } else if (bills[i] == 10) { // 10元则找5元
+ tenHave++;
+ fiveHave--;
+ } else if (bills[i] == 20) { // 20元可以选择给他10+5或者3个5元
+ if (tenHave >= 1) {
+ tenHave--;
+ fiveHave--;
+ } else {
+ fiveHave -= 3;
+ }
+ }
+ // 如果钞票不够找
+ if (fiveHave < 0 || tenHave < 0) {
+ return false;
+ }
+ }
+ return true;
+ }
+
+
+ }
+}
diff --git a/src/main/java/cn/whaifree/leetCode/T.java b/src/main/java/cn/whaifree/leetCode/T.java
new file mode 100644
index 0000000..f819f69
--- /dev/null
+++ b/src/main/java/cn/whaifree/leetCode/T.java
@@ -0,0 +1,102 @@
+package cn.whaifree.leetCode;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/2/27 17:58
+ * @注释
+ */
+public class T {
+
+ public int A() {
+ B();
+ return 1;
+ }
+
+ public void B() {
+
+ }
+}
+
+interface Animal {
+ void eat();
+}
+
+class Hunter{
+ void hunt() {
+
+ }
+}
+
+class Cat extends Hunter implements Animal {
+
+ @Override
+ void hunt() {
+ System.out.println("cat hunt");
+ }
+
+ @Override
+ public void eat() {
+ System.out.println("cat eat");
+ }
+}
+
+class Dog extends Hunter implements Animal {
+
+ public Dog() {
+ super();
+ }
+
+ public Dog(String name) {
+ super();
+ }
+
+ @Override
+ void hunt() {
+ System.out.println("dog hunt");
+ }
+
+ @Override
+ public void eat() {
+ System.out.println("dog eat");
+ }
+}
+
+class AnimalTest {
+ public static void main(String[] args) {
+ // 晚期绑定，动态链接
+ // 运行时才能确定
+ Animal animal = new Cat();
+ animal.eat();
+ Hunter hunter = (Hunter) animal;
+ hunter.hunt();
+
+ // 静态多态
+ Dog dog = new Dog("!23");
+
+
+ }
+}
+
+
+class Father{
+ public static void print(String str){
+ System. out. println("father "+str);
+ }
+ public void show(String str){
+ System. out. println("father"+str);
+ }
+}
+
+class Son extends Father {
+
+
+}
+
+class VirtualMethodTest {
+ public static void main(String[] args) {
+ Son.print("coder");
+ Father fa = new Father();
+ fa.show("a");
+ }
+}
diff --git a/src/main/java/cn/whaifree/leetCode/Test.java b/src/main/java/cn/whaifree/leetCode/Test.java
index 31c35f0..74fe730 100644
--- a/src/main/java/cn/whaifree/leetCode/Test.java
+++ b/src/main/java/cn/whaifree/leetCode/Test.java
@@ -11,66 +11,130 @@ import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
/**
- *
* 给定一个整数数组 nums 和一个整数目标值 target，请你在该数组中找出 和为目标值 target 的那 两个 整数，并返回它们的数组下标。
- *
+ *
* 你可以假设每种输入只会对应一个答案。但是，数组中同一个元素在答案里不能重复出现。
- *
+ *
* 你可以按任意顺序返回答案。
- *
+ *
* 来源：力扣（LeetCode）
* 链接：https://leetcode.cn/problems/two-sum
* 著作权归领扣网络所有。商业转载请联系官方授权，非商业转载请注明出处。
- *
- *
- *
+ *
+ *
+ *
* 输入：nums = [2,7,11,15], target = 9
* 输出：[0,1]
* 解释：因为 nums[0] + nums[1] == 9 ，返回 [0, 1] 。
*
- *
* @author whaifree
* @package cn.whaifree.leetCode
* @Date: 2022/9/13 20:54
*/
-public class Test {
+public class Test {
+
+ private static int number;
+
+ private int getNumber;
- static {
- num = 20;
- // 防止在初始化前程序中访问默认值
+ public int minus() {
+ localVarl();
+ int i = 1;
+ double d = 2d;
+ char c = 'd';
+ return (int) (i + d);
}
- private static int num = 10;
+
+ public void localVarl() {
+ int a = 0;
+ System.out.println(a);
+ int b = 0;
+ }
+
+ public void localVar2() {
+ {
+ int a = 0;
+ System.out.println(a);
+ }
+ //此时的就会复用a的槽位
+ int b = 0;
+ }
+
public static void main(String[] args) {
- ClassLoader systemClassLoader = ClassLoader.getSystemClassLoader();
- System.out.println(systemClassLoader);
- ClassLoader extClassLoader = systemClassLoader.getParent();
- System.out.println(extClassLoader);
-
- // 获取不到引导类类加载器
- ClassLoader bootClassLoader = extClassLoader.getParent();
- System.out.println(bootClassLoader);
-
- ClassLoader classLoader = Test.class.getClassLoader();
- System.out.println(classLoader);
+ //第1类问题
+ int i1 = 10;
+ i1++;
+ int i2 = 10;
+ ++i2;
- // 系统核心类库都是使用引导类（BootStrapClassLoader）进行加载，都为null
- ClassLoader stringLoader = String.class.getClassLoader();
- System.out.println(stringLoader);
+ //第2类问题:
+ int i3 = 10;
+ int i4 = i3++;
+ int i5 = 10;
+ int i6 = ++i5;
- PriorityQueue objects = new PriorityQueue<>();
- objects.add(1);
- objects.add(2);
- objects.add(3);
- objects.add(4);
- System.out.println(objects.poll());
- System.out.println(objects.poll());
+ //第3类问题:
+ int i7 = 10;
+ i7 = i7++;
+ int i8 = 10;
+ i8 = ++i8;
+
+ // 第四类问题
+ int i9 = 10;
+ int i10 = i9++ + ++i9;
+
+// // 挨个输出i1-i10
+// System.out.println(i1);
+// System.out.println(i2);
+// System.out.println(i3);
+// System.out.println(i4);
+// System.out.println(i5);
+// System.out.println(i6);
+// System.out.println(i7);
+// System.out.println(i8);
+// System.out.println(i9);
+// System.out.println(i10);
+//
+//
+//
+// System.out.println(new Test().getNumber);
+//
+// System.out.println(Test.number);
+// // 递归删除某个目录下所有文件名为(1)的文件
+//
+//
+// ClassLoader systemClassLoader = ClassLoader.getSystemClassLoader();
+// System.out.println(systemClassLoader);
+//
+// ClassLoader extClassLoader = systemClassLoader.getParent();
+// System.out.println(extClassLoader);
+//
+// // 获取不到引导类类加载器
+// ClassLoader bootClassLoader = extClassLoader.getParent();
+// System.out.println(bootClassLoader);
+//
+// ClassLoader classLoader = Test.class.getClassLoader();
+// System.out.println(classLoader);
+//
+//
+// // 系统核心类库都是使用引导类（BootStrapClassLoader）进行加载，都为null
+// ClassLoader stringLoader = String.class.getClassLoader();
+// System.out.println(stringLoader);
+//
+//
+// PriorityQueue objects = new PriorityQueue<>();
+// objects.add(1);
+// objects.add(2);
+// objects.add(3);
+// objects.add(4);
+// System.out.println(objects.poll());
+// System.out.println(objects.poll());
}
-
}