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From: =?UTF-8?q?=E7=A7=A6=E8=8B=B1=E6=9D=B0?= <327782001@qq.com>
Date: Tue, 11 Jul 2023 10:23:39 +0800
Subject: [PATCH] =?UTF-8?q?fix:=E6=9C=80=E5=A4=A7=E5=AD=90=E5=BA=8F?=
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---
 .../day04/problem_solving_06.py"              |  1 -
 .../day04/problem_solving_07.py"              |  1 -
 .../day04/problem_solving_08_01.py"           | 23 +++++++++++++++
 .../day04/problem_solving_08_02.py"           | 28 +++++++++++++++++++
 4 files changed, 51 insertions(+), 2 deletions(-)
 create mode 100644 "01-\346\225\260\347\273\204/day04/problem_solving_08_01.py"
 create mode 100644 "01-\346\225\260\347\273\204/day04/problem_solving_08_02.py"

diff --git "a/01-\346\225\260\347\273\204/day04/problem_solving_06.py" "b/01-\346\225\260\347\273\204/day04/problem_solving_06.py"
index 555ed05..cb36ebf 100644
--- "a/01-\346\225\260\347\273\204/day04/problem_solving_06.py"
+++ "b/01-\346\225\260\347\273\204/day04/problem_solving_06.py"
@@ -1,7 +1,6 @@
 """
  两数之和 II - 输入有序数组
 """
-import heapq
 from typing import List
 
 
diff --git "a/01-\346\225\260\347\273\204/day04/problem_solving_07.py" "b/01-\346\225\260\347\273\204/day04/problem_solving_07.py"
index c0f8f76..0cc542a 100644
--- "a/01-\346\225\260\347\273\204/day04/problem_solving_07.py"
+++ "b/01-\346\225\260\347\273\204/day04/problem_solving_07.py"
@@ -1,7 +1,6 @@
 """
 最接近的三数之和
 """
-import heapq
 from typing import List
 
 
diff --git "a/01-\346\225\260\347\273\204/day04/problem_solving_08_01.py" "b/01-\346\225\260\347\273\204/day04/problem_solving_08_01.py"
new file mode 100644
index 0000000..06f4152
--- /dev/null
+++ "b/01-\346\225\260\347\273\204/day04/problem_solving_08_01.py"
@@ -0,0 +1,23 @@
+"""
+最大子序列交替和
+"""
+from typing import List
+
+
+class Solution:
+    def maxAlternatingSum(self, nums: List[int]) -> int:
+        """
+        最大子序列交替和:偶数尽量大,奇数尽量小,且最后一个奇数可以不要
+        可以使用贪心算法
+        :param nums:
+        :return:
+        """
+        res = nums[0]
+        for i in range(1, len(nums)):
+            res += max(nums[i] - nums[i - 1], 0)
+        return res
+
+
+if __name__ == '__main__':
+    result = Solution().maxAlternatingSum([-4, 6, 5, 3])
+    print(result)
diff --git "a/01-\346\225\260\347\273\204/day04/problem_solving_08_02.py" "b/01-\346\225\260\347\273\204/day04/problem_solving_08_02.py"
new file mode 100644
index 0000000..e7dd004
--- /dev/null
+++ "b/01-\346\225\260\347\273\204/day04/problem_solving_08_02.py"
@@ -0,0 +1,28 @@
+"""
+最大子序列交替和
+"""
+from typing import List
+
+
+class Solution:
+    def maxAlternatingSum(self, nums: List[int]) -> int:
+        """
+        动态规划  打家劫舍  背包问题
+        even 偶数
+        odd 奇数
+        """
+        even, odd = 0, nums[0]  # 偶数`长度`子序列的最大交替和，初始为0；奇数`长度`子序列的最大交替和，初始为首个元素
+        res = odd  # 所有子序列的最大最大交替和，由于元素非负，因此初始为even和odd的最大值即为odd=nums[0]
+        for i in range(1, len(nums)):
+            # 从第二个元素开始进行动规
+            # 动态规划更新even和odd
+            even = max(even, odd - nums[i])
+            odd = max(odd, even + nums[i])
+            # 更新最大最大交替和
+            res = max(res, even, odd)
+        return res
+
+
+if __name__ == '__main__':
+    result = Solution().maxAlternatingSum([4, 6, 5, 3])
+    print(result)
-- 
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