2020-08-22

Author: JiayangWu

1544.整理字符串/1544-整理字符串.py

@@ -0,0 +1,13 @@
+class Solution(object):
+    def makeGood(self, s):
+        """
+        :type s: str
+        :rtype: str
+        """
+        stack = []
+        for ch in s:
+            if not stack or abs(ord(stack[-1]) - ord(ch)) != 32:
+                stack.append(ch)
+            else:
+                stack.pop()
+        return "".join(ch for ch in stack)

1545.找出第N个二进制字符串中的第K位/1545-找出第N个二进制字符串中的第K位.py

@@ -0,0 +1,25 @@
+class Solution(object):
+    def findKthBit(self, n, k):
+        """
+        :type n: int
+        :type k: int
+        :rtype: str
+        """
+
+        def invert(s):
+            res = ""
+            for ch in s:
+                if ch == "0":
+                    res += "1"
+                else:
+                    res += "0"
+            return res
+
+        i = 1
+        s = "0"
+        while i < n:
+            s = s + "1" + invert(s)[::-1]
+            i += 1
+            if k - 1 < len(s):
+                return s[k - 1]
+        return s[k - 1]

1546.和为目标值的最大数目不重叠非空子数组数目/1546-和为目标值的最大数目不重叠非空子数组数目.py

@@ -0,0 +1,19 @@
+class Solution(object):
+    def maxNonOverlapping(self, nums, target):
+        """
+        :type nums: List[int]
+        :type target: int
+        :rtype: int
+        """
+        pre_sum = {0}
+        res = 0
+        s = 0
+        for num in nums:
+            s += num
+            if s - target in pre_sum:
+                res += 1
+                s = 0
+                pre_sum = {0}
+            else:
+                pre_sum.add(s)
+        return res