Python双指针题型同向双指针滑动窗口

　　同向双指针可以被想象成一只蚯蚓：在不满足条件时，右指针(蚯蚓头)不断向前伸；满足条件时，右指针不动，左指针(蚯蚓尾)向前蠕动。模板是:end = 0 for start from 0 to (n-1): 			while end < n and (condition is not True):       				end += 1        if (condition is True):        	   Process_start_and_endMinimum Size Subarray Sum
　　给定一个正整数数组 nums  和一个目标正整数，返回其和大于或等于 目标的  连续子数组的最小长度。如果没有这样的子数组，则返回 0。  class Solution:     def minSubArrayLen(self, target: int, nums: List[int]) -> int:         end, res, cursum = 0, sys.maxsize, 0         for start in range(len(nums)):             while end < len(nums) and cursum < target:                 cursum += nums[end]                 end += 1             if cursum >= target:                 res = min(res, end - start)                 cursum -= nums[start]             elif end == len(nums):                 break         if res == math.inf: res = 0         return resLongest Substring Without Repeating Characters
　　定一个字符串 s  ，找出最长的不重复字符的子串的长度。 class Solution:     def lengthOfLongestSubstring(self, s: str) -> int:         n, end, res = len(s), 0, 0         chars = [0] * 128          for start in range(n):             while end < n and chars[ord(s[end])]==0:                 chars[ord(s[end])] = 1                 end += 1                         res = max(res, end - start)             chars[ord(s[start])] = 0             if n - start < res: break         return res