feat(redo): 添加新的练习代码和解决方案

- 新增 LeetCode 69、135、376、763题目的解决方案
- 添加面试题练习代码
- 新建 SQL 查询练习题 stu，列 name, score, course，查询每一科分数大于 60 的学生姓名

ForJdk17/src/main/java/cn/whaifree/interview/jr/p1.java

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+package cn.whaifree.interview.jr;
+
+import java.util.Scanner;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/10/22 12:11
+ * @注释
+ */
+public class p1 {
+
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+
+        int people = in.nextInt();
+        int gzNum = in.nextInt();
+        int[] nums = new int[people];
+        for (int i = 0; i < people; i++) {
+            nums[i] = in.nextInt();
+        }
+
+        int[] gzNums = new int[gzNum];
+
+        for (int i = 0; i < nums.length; i++) {
+            int want = nums[i];
+            gzNums[want - 1]++;
+        }
+
+        int res = 0;
+        for (int num : gzNums) {
+            int needSum = num / 2;
+            if (num % 2 == 1) {
+                res += (needSum + 1);
+            } else {
+                res += (needSum);
+            }
+        }
+        System.out.println(res);
+    }
+}
+
+
+class p2{
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        // 注意 hasNext 和 hasNextLine 的区别
+        int v0 = in.nextInt(); // 初始速度
+        int x = in.nextInt(); // v=v0+t*x
+        int y = in.nextInt(); // 总里程
+        // t1 = y / v = y / (v0+t*x)
+        // t = 2 / (t) t
+
+        // 速度t 2   2/t=2.8284271  t = 2/更好8 = 根号2/2
+        double t = Math.sqrt(2) / 2;
+        System.out.println(y / (v0 + t * x));
+
+    }
+}

ForJdk17/src/main/java/cn/whaifree/redo/redo_all_241016/LeetCode135.java

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+package cn.whaifree.redo.redo_all_241016;
+
+import org.junit.Test;
+
+import java.util.Arrays;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/10/22 16:55
+ * @注释
+ */
+public class LeetCode135 {
+
+    @Test
+    public void test() {
+        int[] ratings = {1, 0, 2};
+        // 1 2 3 4 3 2 1
+        int result = new Solution().candy(ratings);
+        System.out.println(result);
+    }
+
+
+    class Solution {
+        /**
+         * 先全部分配1
+         *
+         * 1 0 2
+         * 1 1 1
+         * 2 1 1
+         * 2 1 2
+         *
+         * @param ratings
+         * @return
+         */
+        public int candy(int[] ratings) {
+            int[] dis = new int[ratings.length];
+            Arrays.fill(dis, 1);
+            for (int i = 0; i < ratings.length - 1; i++) {
+                if (ratings[i + 1] > ratings[i]) {
+                    dis[i + 1] = dis[i] + 1;
+                }
+            }
+            for (int j = ratings.length - 2; j >= 0; j--) {
+                if (ratings[j] > ratings[j + 1]) {
+                    dis[j] = Math.max(dis[j], dis[j + 1] + 1); // 保留之前的
+                }
+            }
+            System.out.println(Arrays.toString(dis));
+
+            return Arrays.stream(dis).sum();
+        }
+    }
+}

ForJdk17/src/main/java/cn/whaifree/redo/redo_all_241016/LeetCode376.java

@@ -0,0 +1,127 @@
+package cn.whaifree.redo.redo_all_241016;
+
+import org.junit.Test;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/10/22 13:57
+ * @注释
+ */
+public class LeetCode376 {
+
+    @Test
+    public void test() {
+        int[] nums = {1,1,7,4,9,2,5};
+        Solution solution = new Solution();
+        int res = solution.wiggleMaxLength(nums);
+        System.out.println(res);
+    }
+
+
+    class Solution {
+
+        public int wiggleMaxLength(int[] nums) {
+            if (nums.length <= 1) {
+                return nums.length;
+            }
+
+            int pre = 0; // 0是可以进入的
+
+            int right = 1;
+            int res =  1; // 注意第一个
+            while (right < nums.length) {
+                int now = nums[right] - nums[right - 1];
+                if (now < 0 && pre >= 0) { // 如果本次<0，上个区间>0
+                    res++;
+                    pre = now;
+                    right++;
+                } else if (now > 0 && pre <= 0) { // 如果本次>0，上个区间<0
+                    res++;
+                    pre = now;
+                    right++;
+                } else {
+                    // 如果上一个区间和本区间都是递增或者递减
+                    right++;
+                }
+            }
+            return res;
+        }
+
+//        public int wiggleMaxLength(int[] nums) {
+//            if (nums.length <= 1) {
+//                return nums.length;
+//            }
+//
+//            boolean up = nums[1] - nums[0] > 0;
+//
+//            int left = 1;
+//            int right = 2;
+//            int res = nums[1] - nums[0] != 0 ? 2 : 1; // 注意第一个
+//            while (right < nums.length) {
+//                int now = nums[right] - nums[left];
+//                if (now < 0 && up) { // 如果本次<0，上个区间>0
+//                    res++;
+//                    up = !up;
+//                    left++;
+//                    right++;
+//                }else if (now > 0 && !up) { // 如果本次>0，上个区间<0
+//                    res++;
+//                    up = !up;
+//                    left++;
+//                    right++;
+//                }else {
+//                    // 如果上一个区间和本区间都是递增或者递减
+//                    right++;
+//                }
+//            }
+//            return res;
+//        }
+
+
+    }
+
+    @Test
+    public void test1() {
+        int[] nums = {0,0};
+        Solution1 solution1 = new Solution1
+                ();
+        System.out.println(solution1.wiggleMaxLength(nums));
+    }
+
+    class Solution1 {
+        /**
+         * up[i] 表示0-i最长上升摆动序列的长度（可以不包括最后一个元素，只要这个序列的最后一个摆动是上升的）
+         *      up[i-1] 不是摇摆
+         *      max( up[i-1], down[i-1] +1)  nums[i] < nums[i-1]  表示递减，则使用前面的最长序列+1
+         *      之前的序列可能更长，或者本down+1
+         * down[i] 表示0-i最长下降摆动序列
+         *      down[i-1]
+         *      max ( down[i-1], up[i-1]+1)
+         * @param nums
+         * @return
+         */
+        public int wiggleMaxLength(int[] nums) {
+            if (nums.length <= 1) {
+                return nums.length;
+            }
+            int[] down = new int[nums.length];
+            int[] up = new int[nums.length];
+            down[0] = 1;
+            up[0] = 1;
+            for (int i = 1; i < nums.length; i++) {
+                if (nums[i] > nums[i - 1]) { // 递增
+                    down[i] = Math.max(down[i - 1], up[i - 1] + 1);
+                    up[i] = up[i - 1];
+                } else if (nums[i] < nums[i - 1]) {
+                    up[i] = Math.max(up[i - 1], down[i - 1] + 1);
+                    down[i] = down[i - 1];
+                }else {
+                    up[i] = up[i - 1];
+                    down[i] = down[i - 1];
+                }
+            }
+            return Math.max(down[nums.length - 1], up[nums.length - 1]);
+        }
+    }
+}

ForJdk17/src/main/java/cn/whaifree/redo/redo_all_241016/LeetCode69.java

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+package cn.whaifree.redo.redo_all_241016;
+
+import org.junit.Test;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/10/22 17:18
+ * @注释
+ */
+public class LeetCode69 {
+    @Test
+    public void test() {
+        Solution1 solution = new Solution1();
+        int i = solution.mySqrt(8);
+        System.out.println(i);
+    }
+
+    class Solution1 {
+        public int mySqrt(int x) {
+            int left = 0;
+            int right = x;
+            while (left <= right) {
+                int mid = (left + right) / 2;
+                long pro = (long) mid * mid;
+                if (pro > x) {
+                    right = mid - 1;
+                }else if (pro < x){
+                    left = mid + 1;
+                }else {
+                    return mid;
+                }
+            }
+            return right;
+        }
+    }
+
+    class Solution {
+        /**
+         *
+         * x^1/2 =k
+         * k^2 = x
+         * logk x = 2
+         * ln k
+         * ln x = 2
+         *
+         * ln k = 2 ln x
+         * e(ln k) = e2lnx = x2
+         *
+         * @param x
+         * @return
+         */
+        public int mySqrt(int x) {
+            double log = Math.log(x);
+            log /= 2;
+            int ans = (int) Math.exp(log);
+            if ((long) (ans + 1) * (ans + 1) <= x) {
+                return ans + 1;
+            }
+            return ans;
+
+        }
+    }
+}

ForJdk17/src/main/java/cn/whaifree/redo/redo_all_241016/LeetCode763.java

@@ -0,0 +1,48 @@
+package cn.whaifree.redo.redo_all_241016;
+
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/10/22 17:10
+ * @注释
+ */
+public class LeetCode763
+{
+
+    @Test
+    public void test() {
+        String s = "ababcbacadefegdehijhklij";
+        List<Integer> ans = new Solution().partitionLabels(s);
+        System.out.println(ans);
+    }
+
+    class Solution {
+        public List<Integer> partitionLabels(String s) {
+            Map<Character, Integer> lastIndex = new HashMap<>();
+            for (int i = 0; i < s.length(); i++) {
+                lastIndex.put(s.charAt(i), i);
+            }
+            List<Integer> ans = new ArrayList<>();
+            // 在便利的过程中获取最远处
+            char[] charArray = s.toCharArray();
+            int left = 0;
+            int most = 0;
+            for (int i = 0; i < charArray.length; i++) {
+                char c = charArray[i];
+                most = Math.max(most, lastIndex.get(c));
+                if (most == i) {
+                    ans.add(i - left + 1);
+                    left = i + 1;
+                }
+            }
+            return ans;
+        }
+    }
+}

sql/looking/241022_1.sql

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+-- stu，列 name, score, course，查询每一科分数大于 60 的学生姓名
+
+
+-- 创建表
+create table stu(
+    id int primary key auto_increment,
+    name varchar(20),
+    score int,
+    course varchar(20)
+);
+-- 生成一些数据
+insert into stu(name, score, course)
+values ('张三', 70, '语文'),
+       ('李四', 80, '语文'),
+       ('王五', 60, '语文'),
+       ('赵六', 90, '语文');
+
+SELECT DISTINCT stu.name FROM stu where stu.name
+    not in( SELECT stu.name FROM stu WHERE stu.score<60);
+
+SELECT name
+FROM stu
+GROUP BY name
+HAVING MIN(score) > 60;