diff --git a/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode122.java b/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode122.java
new file mode 100644
index 0000000..a6b5955
--- /dev/null
+++ b/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode122.java
@@ -0,0 +1,80 @@
+package cn.whaifree.redo.redo_all_240721;
+
+import org.junit.Test;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/8/4 18:30
+ * @注释
+ */
+public class LeetCode122 {
+
+    @Test
+    public void test()
+    {
+        int[] prices = {7,1,5,3,6,4};
+        System.out.println(maxProfit1(prices));
+
+        System.out.println(new Solution().maxProfit(prices));
+    }
+
+    public int maxProfit(int[] prices)
+    {
+        int nowProfit = 0;
+        int right = 1;
+        while (right < prices.length) {
+            if (prices[right] > prices[right - 1]) {
+                nowProfit += prices[right] - prices[right - 1];
+            }
+            right++;
+        }
+        return nowProfit;
+    }
+
+    public int maxProfit1(int[] prices)
+    {
+        int nowProfit = 0;
+        int right = 1;
+        int left = 0;
+        while (right < prices.length) {
+            while (left < right && prices[left] > prices[right]) {
+                left++;
+            }
+            if (prices[left] < prices[right]) {
+                nowProfit += (prices[right] - prices[left]);
+                left = right;
+            }
+            right++;
+        }
+        return nowProfit;
+    }
+
+    class Solution {
+        /**
+         * dp[i][0] 表示第i天手头没有股票的最大利润
+         *      - 刚卖 dp[i-1][1]+price[i]
+         *      - 前一天就没有 dp[i-1][0]
+         * do[i][1] 表示第i天手头有股票的最大利润
+         *      - 前一天就有  dp[i-1][1]
+         *      - 刚买入 dp[i-1][0] - price[i]
+         *
+         *   [7,1,5,3,6,4]
+         * 0  0 0 4 4
+         * 1 -7-1-1
+         *
+         * @param prices
+         * @return
+         */
+        public int maxProfit(int[] prices) {
+            int[][] dp = new int[prices.length][2];
+            dp[0][0] = 0;
+            dp[0][1] = -prices[0];
+            for (int i = 1; i < prices.length; i++) {
+                dp[i][0] = Math.max(dp[i - 1][0], dp[i - 1][1] + prices[i]);
+                dp[i][1] = Math.max(dp[i - 1][1], dp[i - 1][0] - prices[i]);
+            }
+            return dp[prices.length - 1][0];
+        }
+    }
+}
diff --git a/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode376.java b/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode376.java
new file mode 100644
index 0000000..5c9cd8f
--- /dev/null
+++ b/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode376.java
@@ -0,0 +1,70 @@
+package cn.whaifree.redo.redo_all_240721;
+
+import org.junit.Test;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/8/4 16:38
+ * @注释
+ */
+public class LeetCode376 {
+
+    @Test
+    public void test()
+    {
+        System.out.println(wiggleMaxLength(new int[]{0,0}));
+        System.out.println(wiggleMaxLength(new int[]{1,17,5,10,13,15,10,5,16,8}));
+
+    }
+
+
+    public int wiggleMaxLength(int[] nums)
+    {
+        if (nums.length <= 1) {
+            return nums.length;
+        }
+        int res = 1;
+        int preSub = 0;
+        int nowSub = 0;
+        for (int i = 1; i < nums.length; i++) {
+            nowSub = nums[i] - nums[i - 1];
+            if ((nowSub > 0 && preSub <= 0) || nowSub < 0 && preSub >= 0) {
+                res++;
+                preSub = nowSub;
+            }
+        }
+        return res;
+    }
+
+//    public int wiggleMaxLength(int[] nums)
+//    {
+//        if (nums.length <= 1) {
+//            return nums.length;
+//        }
+//
+//        int left = 1;
+//        int right = 2;
+//        int res = 1;
+//        boolean up = nums[1] - nums[0] > 0;
+//        if (nums[1] - nums[0] != 0) {
+//            res++;
+//        }
+//        while (right < nums.length) {
+//            if (nums[right] < nums[left] && up) {
+//                // 是要的
+//                res++;
+//                up = false;
+//                left++;
+//            }else if (nums[right] > nums[left] && !up){
+//                // 是要的
+//                res++;
+//                up = true;
+//                left++;
+//            }
+//            right++;
+//        }
+//        return res;
+//    }
+
+}
diff --git a/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode45.java b/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode45.java
new file mode 100644
index 0000000..44b05c9
--- /dev/null
+++ b/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode45.java
@@ -0,0 +1,75 @@
+package cn.whaifree.redo.redo_all_240721;
+
+import org.junit.Test;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/8/4 21:52
+ * @注释
+ */
+public class LeetCode45 {
+
+    @Test
+    public void test()
+    {
+        int[] nums = {1,2,3};
+        System.out.println(jump1(nums));
+    }
+
+    /**
+     * 2,3,5,0,1,4
+     * [2 3 5] 内只会有一个能到最远的
+     * @param nums
+     * @return
+     */
+    public int jump(int[] nums)
+    {
+        if (nums.length == 1) {
+            return 0;
+        }
+        int left = 0;
+        int right = 0;
+        int maxCover = 0;
+        int minJump = 0;
+        while (left < nums.length) {
+            maxCover = Math.max(maxCover, left + nums[left]);
+            if (left == right) {
+                right = maxCover;
+                minJump++;
+            }
+            if (right >= nums.length - 1) {
+                break;
+            }
+            left++;
+        }
+        return minJump;
+    }
+
+    public int jump1(int[] nums)
+    {
+        if (nums.length == 1) {
+            return 0;
+        }
+        int left = 0;
+        int right = 0;
+        int nowJump = 0;
+        int minJump = Integer.MAX_VALUE;
+        while (left < nums.length) {
+            int tmpFar = left + nums[left];
+            while (left <= right) {
+                if (left + nums[left] > tmpFar) {
+                    tmpFar = left + nums[left];
+                }
+                left++;
+            }
+            nowJump++;
+            if (tmpFar >= nums.length - 1) {
+                minJump = Math.min(minJump, nowJump);
+                break;
+            }
+            right = tmpFar;
+        }
+        return minJump == Integer.MAX_VALUE ? 1 : minJump;
+    }
+}
diff --git a/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode53.java b/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode53.java
new file mode 100644
index 0000000..6e98b13
--- /dev/null
+++ b/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode53.java
@@ -0,0 +1,75 @@
+package cn.whaifree.redo.redo_all_240721;
+
+import org.junit.Test;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/8/4 17:52
+ * @注释
+ */
+public class LeetCode53 {
+
+    @Test
+    public void test()
+    {
+
+        int[] nums = new int[]{-2,1,-3,4,-1,2,1,-5,4};
+        Solution1 solution = new Solution1();
+        System.out.println(solution.maxSubArray(nums));
+        System.out.println(solution.maxSubArray(new int[]{5,4,-1,7,8}));
+
+    }
+
+    class Solution {
+        public int maxSubArray(int[] nums) {
+            int nowSum = 0;
+            int right = 0;
+            int max = Integer.MIN_VALUE;
+            while (right < nums.length) {
+                nowSum += nums[right];
+                max = Math.max(max, nowSum);
+                if (nowSum < 0) {
+                    nowSum = 0;
+                }
+                right++;
+            }
+            return max;
+        }
+    }
+
+    class Solution1 {
+        /**
+         * dp
+         *
+         * dp[i] 表示包含第i个元素的最大和的连续子数组的和
+         * dp[0] = nums[0]
+         *   [-2,1,-3,4,-1,2,1,-5,4]
+         * dp -2 1 -3 4  3 5 6 1 5
+         *
+         * if nums[i]+dp[i-1]>0
+         *    dp[i] = nums[i]+dp[i-1]
+         * else
+         *    dp[i] = nums[i]
+         *
+         * @param nums
+         * @return
+         */
+        public int maxSubArray(int[] nums) {
+
+            int[] dp = new int[nums.length];
+            dp[0] = nums[0];
+            int max = dp[0];
+            for (int i = 1; i < nums.length; i++) {
+                if (dp[i - 1] > 0 && nums[i] + dp[i - 1] > 0) {
+                    // dp[i-1]>0 才能用，不然只能拖累
+                    dp[i] = nums[i] + dp[i - 1];
+                } else {
+                    dp[i] = nums[i];
+                }
+                max = Math.max(max, dp[i]);
+            }
+            return max;
+        }
+    }
+}
diff --git a/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode55.java b/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode55.java
new file mode 100644
index 0000000..57c9bc8
--- /dev/null
+++ b/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode55.java
@@ -0,0 +1,50 @@
+package cn.whaifree.redo.redo_all_240721;
+
+import org.junit.Test;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/8/4 19:03
+ * @注释
+ */
+public class LeetCode55 {
+
+    @Test
+    public void test()
+    {
+        int[] nums = {2,3,1,1,4};
+        System.out.println(new Solution().canJump(nums));
+
+        System.out.println(new Solution().canJump(new int[]{3, 2, 1, 0, 5}));
+        System.out.println(new Solution().canJump(new int[]{1,2,3}));
+
+    }
+
+    class Solution {
+        /**
+         *
+         *
+         * @param nums
+         * @return
+         */
+        public boolean canJump(int[] nums) {
+            if (nums.length == 1) {
+                return true;
+            }
+
+            int right = nums[0];
+            int left = 0;
+            while (left <= right) {
+                if (left + nums[left] > right) {
+                    right = left + nums[left];
+                }
+                if (right >= nums.length - 1) {
+                    return true;
+                }
+                left++;
+            }
+            return false;
+        }
+    }
+}