diff --git "a/01-\346\225\260\347\273\204/day04/problem_solving_01.py" "b/01-\346\225\260\347\273\204/day04/problem_solving_01.py"
new file mode 100644
index 0000000000000000000000000000000000000000..7dce7234d8dee52d50d1cb8f07c16a2715a50458
--- /dev/null
+++ "b/01-\346\225\260\347\273\204/day04/problem_solving_01.py"
@@ -0,0 +1,29 @@
+"""
+盛最多水的容器
+"""
+from typing import List
+
+
+class Solution:
+    def maxArea(self, height: List[int]) -> int:
+        """
+        双指针
+        :param height:
+        :return:
+        """
+        max_area = 0
+        left = 0
+        right = len(height) - 1
+        while left < right:
+            area = (right - left) * min(height[left], height[right])
+            max_area = max(max_area, area)
+            if height[left] < height[right]:
+                left += 1
+            else:
+                right -= 1
+        return max_area
+
+
+if __name__ == '__main__':
+    result = Solution().maxArea([1, 8, 6, 2, 5, 4, 8, 3, 7])
+    print(result)
diff --git "a/01-\346\225\260\347\273\204/day04/problem_solving_02_01.py" "b/01-\346\225\260\347\273\204/day04/problem_solving_02_01.py"
new file mode 100644
index 0000000000000000000000000000000000000000..94059dc860ef40c34319a30a6869a5b66e569e08
--- /dev/null
+++ "b/01-\346\225\260\347\273\204/day04/problem_solving_02_01.py"
@@ -0,0 +1,22 @@
+"""
+K 件物品的最大和
+"""
+from typing import List
+
+
+class Solution:
+    def kItemsWithMaximumSum(self, numOnes: int, numZeros: int, numNegOnes: int, k: int) -> int:
+        if k <= numOnes:
+            return k
+        elif numOnes < k <= (numOnes + numZeros):
+            return numOnes
+        elif (numOnes + numZeros) < k <= (numOnes + numZeros + numNegOnes):
+            return numOnes - (k - numOnes - numZeros)
+        else:
+            return numOnes - numNegOnes
+        return result
+
+
+if __name__ == '__main__':
+    result = Solution().kItemsWithMaximumSum(3, 2, 0, 2)
+    print(result)
diff --git "a/01-\346\225\260\347\273\204/day04/problem_solving_02_02.py" "b/01-\346\225\260\347\273\204/day04/problem_solving_02_02.py"
new file mode 100644
index 0000000000000000000000000000000000000000..42a7ea98283c420ad6d361bb684f69a2dbf9c095
--- /dev/null
+++ "b/01-\346\225\260\347\273\204/day04/problem_solving_02_02.py"
@@ -0,0 +1,14 @@
+"""
+K 件物品的最大和
+"""
+from typing import List
+
+
+class Solution:
+    def kItemsWithMaximumSum(self, numOnes: int, numZeros: int, numNegOnes: int, k: int) -> int:
+        return numOnes - (k - numOnes + numZeros) if k > (numOnes + numZeros) else min(numOnes, k)
+
+
+if __name__ == '__main__':
+    result = Solution().kItemsWithMaximumSum(3, 2, 0, 2)
+    print(result)
diff --git "a/01-\346\225\260\347\273\204/day04/problem_solving_03.py" "b/01-\346\225\260\347\273\204/day04/problem_solving_03.py"
new file mode 100644
index 0000000000000000000000000000000000000000..3c458bb174a654391f33efb5850b72ec6d6e451b
--- /dev/null
+++ "b/01-\346\225\260\347\273\204/day04/problem_solving_03.py"
@@ -0,0 +1,36 @@
+"""
+三数之和
+"""
+from typing import List
+
+
+class Solution:
+    def threeSum(self, nums: List[int]) -> List[List[int]]:
+        nums.sort()
+        res = []
+        for i in range(len(nums) - 2):
+            if nums[i] > 0:
+                break
+            if i > 0 and nums[i] == nums[i - 1]:
+                continue
+            left, right = i + 1, len(nums) - 1
+            while left < right:
+                total = nums[i] + nums[left] + nums[right]
+                if total < 0:
+                    left += 1
+                elif total > 0:
+                    right -= 1
+                else:
+                    res.append([nums[i], nums[left], nums[right]])
+                    while left < right and nums[left] == nums[left + 1]:
+                        left += 1
+                    while left < right and nums[right] == nums[right - 1]:
+                        right -= 1
+                    left += 1
+                    right -= 1
+        return res
+
+
+if __name__ == '__main__':
+    result = Solution().threeSum([-1, 0, 1, 2, -1, -4])
+    print(result)