diff --git a/src/main/java/cn/whaifree/redo/redo_all_240511/LeetCode142.java b/src/main/java/cn/whaifree/redo/redo_all_240511/LeetCode142.java
new file mode 100644
index 0000000..f0e4c37
--- /dev/null
+++ b/src/main/java/cn/whaifree/redo/redo_all_240511/LeetCode142.java
@@ -0,0 +1,43 @@
+package cn.whaifree.redo.redo_all_240511;
+
+import cn.whaifree.leetCode.model.ListNode;
+import org.junit.Test;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/6/2 14:49
+ * @注释
+ */
+public class LeetCode142 {
+
+    @Test
+    public void test() {
+        ListNode node = ListNode.listNodeFromArray(new int[]{1,3,2});
+        node.next.next.next = node.next;
+        System.out.println(new Solution().detectCycle(node).val);
+    }
+
+
+    public class Solution {
+        public ListNode detectCycle(ListNode head) {
+            ListNode fast = head;
+            ListNode slow = head;
+            do {
+                if (fast == null || fast.next == null) {
+                    return null;
+                }
+                fast = fast.next.next;
+                slow = slow.next;
+            } while (fast != slow);
+
+
+            fast = head;
+            while (fast != slow) {
+                fast = fast.next;
+                slow = slow.next;
+            }
+            return fast;
+        }
+    }
+}
diff --git a/src/main/java/cn/whaifree/redo/redo_all_240511/LeetCode15_$.java b/src/main/java/cn/whaifree/redo/redo_all_240511/LeetCode15_$.java
new file mode 100644
index 0000000..0696bf3
--- /dev/null
+++ b/src/main/java/cn/whaifree/redo/redo_all_240511/LeetCode15_$.java
@@ -0,0 +1,60 @@
+package cn.whaifree.redo.redo_all_240511;
+
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * FIXME： 24-6-2
+ *
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/6/2 20:43
+ * @注释
+ */
+public class LeetCode15_$ {
+
+    @Test
+    public void test() {
+        int[] nums = {-1, 0, 1, 2, -1, -4};
+        Solution solution = new Solution();
+        List<List<Integer>> lists = solution.threeSum(nums);
+        System.out.println(lists);
+    }
+
+    class Solution {
+        public List<List<Integer>> threeSum(int[] nums) {
+            List<List<Integer>> result = new ArrayList<>();
+            Arrays.sort(nums);
+
+            for (int i = 0; i < nums.length - 2; i++) {
+                if (i > 0 && nums[i] == nums[i - 1]) {
+                    continue;
+                }
+                int left = i + 1;
+                int right = nums.length - 1;
+                while (left < right) {
+                    int sum = nums[i] + nums[left] + nums[right];
+                    if (sum == 0) {
+                        result.add(Arrays.asList(nums[i], nums[left], nums[right]));
+                        while (left < right && nums[left] == nums[left + 1]) {
+                            left++;
+                        }
+                        while (left < right && nums[right] == nums[right - 1]) {
+                            right--;
+                        }
+                        left++;
+                        right--;
+                    } else if (sum < 0) {
+                        left++;
+                    } else {
+                        right--;
+                    }
+                }
+            }
+            return result;
+        }
+    }
+}
diff --git a/src/main/java/cn/whaifree/redo/redo_all_240511/LeetCode202.java b/src/main/java/cn/whaifree/redo/redo_all_240511/LeetCode202.java
new file mode 100644
index 0000000..f52e9fc
--- /dev/null
+++ b/src/main/java/cn/whaifree/redo/redo_all_240511/LeetCode202.java
@@ -0,0 +1,52 @@
+package cn.whaifree.redo.redo_all_240511;
+
+import org.junit.Test;
+
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/6/2 16:25
+ * @注释
+ */
+public class LeetCode202 {
+
+    @Test
+    public void test() {
+        Solution solution = new Solution();
+        boolean happy = solution.isHappy(19);
+        System.out.println(happy);
+    }
+
+    class Solution {
+        /**
+         * 2 4 16 37 56 61  37 出现循环
+         * @param n
+         * @return
+         */
+        public boolean isHappy(int n) {
+            int tmp = n;
+            Set<Integer> set = new HashSet<>();
+            while (tmp != 1) {
+                set.add(tmp);
+                tmp = get(tmp);
+                if (set.contains(tmp)) {
+                    return false;
+                }
+            }
+            return true;
+        }
+
+        public int get(int num) {
+            int sum = 0;
+            while (num != 0) {
+                int retail = num % 10;
+                num /= 10;
+                sum += retail * retail;
+            }
+            return sum;
+        }
+    }
+}
diff --git a/src/main/java/cn/whaifree/redo/redo_all_240511/LeetCode2487.java b/src/main/java/cn/whaifree/redo/redo_all_240511/LeetCode2487.java
new file mode 100644
index 0000000..cf7cbca
--- /dev/null
+++ b/src/main/java/cn/whaifree/redo/redo_all_240511/LeetCode2487.java
@@ -0,0 +1,54 @@
+package cn.whaifree.redo.redo_all_240511;
+
+import cn.whaifree.leetCode.model.ListNode;
+import org.junit.Test;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/6/2 16:34
+ * @注释
+ */
+public class LeetCode2487 {
+    @Test
+    public void test() {
+        ListNode listNode = ListNode.listNodeFromArray(new int[]{1, 1, 1, 1});
+        new Solution().removeNodes(listNode).printList();
+    }
+
+    class Solution {
+        public ListNode removeNodes(ListNode head) {
+            head = reverse(head);
+            // 如果左侧会更大，前移动
+            // 如果左侧会更小，删除左侧
+            ListNode tmp = head;
+            ListNode pre = head;
+            while (tmp!= null) {
+                // 找到比pre小的
+                if (tmp.val < pre.val) {
+                    pre.next = tmp.next;
+                }else {
+                    pre = tmp;
+                }
+                tmp = tmp.next;
+            }
+
+
+            return reverse(head);
+        }
+
+        public ListNode reverse(ListNode head) {
+            return reverseList(null, head);
+        }
+
+        public ListNode reverseList(ListNode pre, ListNode after) {
+            if (after == null) {
+                return pre;
+            }
+            ListNode tmp = after.next;
+            after.next = pre;
+            return reverseList(after, tmp);
+        }
+    }
+
+}
diff --git a/src/main/java/cn/whaifree/redo/redo_all_240511/LeetCode28.java b/src/main/java/cn/whaifree/redo/redo_all_240511/LeetCode28.java
new file mode 100644
index 0000000..5e26305
--- /dev/null
+++ b/src/main/java/cn/whaifree/redo/redo_all_240511/LeetCode28.java
@@ -0,0 +1,30 @@
+package cn.whaifree.redo.redo_all_240511;
+
+import org.junit.Test;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/6/3 10:36
+ * @注释
+ */
+public class LeetCode28 {
+    @Test
+    public void test() {
+        Solution solution = new Solution();
+        int i = solution.strStr("hello", "ll");
+        System.out.println(i);
+        System.out.println(solution.strStr("aaaaa", "bba"));
+        System.out.println(solution.strStr("a", "a"));
+    }
+    class Solution {
+        public int strStr(String haystack, String needle) {
+            for (int i = 0; i < haystack.length() - needle.length() + 1; i++) {
+                if (haystack.substring(i, i + needle.length()).equals(needle)) {
+                    return i;
+                }
+            }
+            return -1;
+        }
+    }
+}
diff --git a/src/main/java/cn/whaifree/redo/redo_all_240511/LeetCode287.java b/src/main/java/cn/whaifree/redo/redo_all_240511/LeetCode287.java
new file mode 100644
index 0000000..5077681
--- /dev/null
+++ b/src/main/java/cn/whaifree/redo/redo_all_240511/LeetCode287.java
@@ -0,0 +1,64 @@
+package cn.whaifree.redo.redo_all_240511;
+
+import org.junit.Test;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/6/2 14:37
+ * @注释
+ */
+public class LeetCode287 {
+
+    @Test
+    public void test() {
+        int[] nums = {3, 1, 3, 4, 2};
+        Solution solution = new Solution();
+        int i = solution.findDuplicate(nums);
+        System.out.println(i);
+    }
+
+    class Solution {
+        /**
+         * 成环路
+         *
+         * 1 3 4 2 2
+         * 0 1 2 3 4
+         *
+         * 0--->1--->3--->2--->4--->2
+         *
+         * 3 1 3 4 2
+         * 0 1 2 3 4
+         *
+         * 0->3-->4-->2
+         *
+         * 快慢指针
+         *，类似链表操作
+         * i=0
+         * next i=nums[i]
+         * nexr.next i=nums[nums[i]]
+         *
+         * @param nums
+         * @return
+         */
+        public int findDuplicate(int[] nums) {
+            int fast = 0;
+            int slow = 0;
+            do {
+                fast = nums[nums[fast]];
+                slow = nums[slow];
+            } while (fast != slow);
+
+            // 找到相交点
+            fast = 0;
+            while (fast != slow) {
+                fast = nums[fast];
+                slow = nums[slow];
+            }
+
+            return fast;
+        }
+    }
+
+
+}
diff --git a/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode151.java b/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode151.java
new file mode 100644
index 0000000..f9fee3e
--- /dev/null
+++ b/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode151.java
@@ -0,0 +1,63 @@
+package cn.whaifree.redo.redo_all_240721;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/7/21 16:48
+ * @注释
+ */
+public class LeetCode151 {
+    public static void main(String[] args) {
+        String s = "   a c    ";
+        System.out.println(reverseWords(s));
+    }
+
+    public static String reverseWords(String s) {
+        // 去掉前后的空格
+        // 去掉中间的空格
+        String[] split = s.split(" ");
+        StringBuilder sb = new StringBuilder();
+        for (int i = split.length - 1; i >= 0; i--) {
+            if (!split[i].equals(" ") && !split[i].isEmpty()) {
+                sb.append(split[i]).append(" ");
+            }
+        }
+        String sbString = sb.toString();
+        if (sbString.length() > 1 && sbString.charAt(sbString.length() - 1) == ' ') {
+            sbString = sbString.substring(0, sbString.length() - 1);
+        }
+        return sbString;
+    }
+
+    class Solution {
+        /**
+         * 反转字符串s中的单词顺序。
+         *
+         * @param s 输入的字符串，可能包含前后空格。
+         * @return 返回反转单词顺序后的字符串，不包含前后空格。
+         */
+        public String reverseWords(String s) {
+            // 去除前后空白串
+            s = s.trim();
+
+            // 将字符串s按一个或多个空格分割成单词数组
+            String[] split = s.split(" +");
+
+            // 使用StringBuilder来高效地构建反转后的字符串
+            StringBuilder stringBuilder = new StringBuilder();
+
+            // 从数组的末尾开始向前遍历，依次添加单词到StringBuilder中，并在单词间加上空格
+            for (int i = split.length - 1; i > 0; i--) {
+                stringBuilder.append(split[i]).append(" ");
+            }
+
+            // 添加数组的第一个单词，即原字符串的第一个单词，到StringBuilder末尾
+            stringBuilder.append(split[0]);
+
+            // 返回构建好的反转后的字符串
+            return stringBuilder.toString();
+        }
+
+    }
+
+}
diff --git a/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode203.java b/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode203.java
new file mode 100644
index 0000000..c972f6f
--- /dev/null
+++ b/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode203.java
@@ -0,0 +1,42 @@
+package cn.whaifree.redo.redo_all_240721;
+
+import cn.whaifree.leetCode.model.ListNode;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/7/21 20:47
+ * @注释
+ */
+public class LeetCode203 {
+
+    public static void main(String[] args)
+    {
+        removeElements(ListNode.listNodeFromArray(new int[]{1, 2, 6, 3, 4, 5, 6}), 6).printList();
+    }
+
+
+    public static ListNode removeElements(ListNode node, int val) {
+        if (node == null) {
+            return null;
+        }
+        ListNode next = removeElements(node.next, val);
+        if (node.val == val) { // 这个node不能用
+            return next;
+        }
+        node.next = next;
+        return node;
+    }
+
+    public static ListNode remove(ListNode node, int val) {
+        if (node == null) {
+            return null;
+        }
+        ListNode next = remove(node.next, val);
+        if (node.val == val) { // 这个node不能用
+            return next;
+        }
+        node.next = next;
+        return node;
+    }
+}
diff --git a/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode209.java b/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode209.java
new file mode 100644
index 0000000..dcb292d
--- /dev/null
+++ b/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode209.java
@@ -0,0 +1,86 @@
+package cn.whaifree.redo.redo_all_240721;
+
+import java.util.Arrays;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/7/21 19:52
+ * @注释
+ */
+public class LeetCode209 {
+    public static void main(String[] args) {
+        int[] nums = {2,3,1,2,4,3};
+        int target = 7;
+        System.out.println(minSubArrayLen2(target,nums));
+    }
+
+    /**
+     * 子数组
+     * 双指针
+     *
+     * - right 向前跑
+     * - left 计算是否超过target
+     * @param target
+     * @param nums
+     * @return
+     */
+    public static int minSubArrayLen(int target, int[] nums) {
+        int left = 0;
+        int right = 0;
+        int minLength = Integer.MAX_VALUE;
+        int tmpSum = 0;
+        while (right < nums.length) {
+            while (left < right && tmpSum >= target) {
+                minLength = Math.min(minLength, right - left);
+
+                tmpSum -= nums[left];
+                left++;
+            }
+            tmpSum += nums[right];
+            right++;
+        }
+
+        while (tmpSum >= target) {
+            minLength = Math.min(minLength, right - left);
+            tmpSum -= nums[left];
+            left++;
+        }
+        return minLength == Integer.MAX_VALUE ? 0 : minLength;
+    }
+
+
+    /**
+     * 前缀和
+     *
+     *   2,3,1,2,4,3 纵坐标
+     *   0 1 2 3 4 5 横坐标
+     * 0 2 5 6 8 12 15 // 面积
+     *
+     * <img src="http://42.192.130.83:9000/picgo/imgs/image-20240329122057505.png">
+     * @param target
+     * @param nums
+     * @return
+     */
+    public static int minSubArrayLen2(int target, int[] nums) {
+        int[] prefixSum = new int[nums.length + 1];
+        for (int i = 1; i < prefixSum.length; i++) {
+            prefixSum[i] = prefixSum[i - 1] + nums[i - 1];
+        }
+
+        int minLength = Integer.MAX_VALUE;
+        for (int i = 1; i < prefixSum.length; i++) {
+            // preSum + target = fill
+            int fill = prefixSum[i] + target;
+            int end = Arrays.binarySearch(prefixSum, fill);
+            if (end < 0) {
+                end = -end - 1;
+            }
+
+            if (end < prefixSum.length) {
+                minLength = Math.min(minLength, end - i);
+            }
+        }
+        return minLength == Integer.MAX_VALUE ? 0 : minLength;
+    }
+}
diff --git a/src/main/java/cn/whaifree/test/Review.java b/src/main/java/cn/whaifree/test/Review.java
new file mode 100644
index 0000000..9d01b18
--- /dev/null
+++ b/src/main/java/cn/whaifree/test/Review.java
@@ -0,0 +1,33 @@
+package cn.whaifree.test;
+
+import java.util.*;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/6/26 20:03
+ * @注释
+ */
+public class Review {
+
+    public static void main(String[] args) {
+        // 输入数组
+        // 找到整形数组 中 超过 整形数组中超过
+        // 1 1 1 2 3
+        int[] ints = new int[]{1, 1, 1, 1, 5, 6, 7, 2, 1};
+        System.out.println(method(ints));
+    }
+
+    public static Set<Integer> method(int[] ints) {
+        Map<Integer, Integer> map = new HashMap<>();
+        Set<Integer> res = new HashSet<>();
+        for (int anInt : ints) {
+            Integer orDefault = map.getOrDefault(anInt, 0) + 1;
+            map.put(anInt, orDefault);
+            if (orDefault > ints.length / 2) {
+                res.add(anInt);
+            }
+        }
+        return res;
+    }
+}