【找出最长等值子数组】python

class Solution:
    def longestEqualSubarray(self, nums: List[int], k: int) -> int:
        n=len(nums)
        if n<2:
            return n
        mx=1
        for i,num in enumerate(nums):
            error=0
            flag=1
            for j in range(i+1,n):
                if nums[j]==num:
                    flag+=1
                    mx=max(mx,flag)
                else:
                    error+=1
                    if error>k:
                        break
        return mx

暴力循环超时

使用双指针改造

class Solution:
    def longestEqualSubarray(self, nums: List[int], k: int) -> int:
        d, ans = defaultdict(list), 1
        for i, x in enumerate(nums): d[x].append(i)
        for lst in d.values():
            i, j, n = 0, 0, len(lst)
            while i < n:
                while j < n and lst[j] - lst[i] <= j - i + k: j += 1
                ans, i = max(ans, j - i), i + 1
        return ans