23.07.04 Today’s Leetcode

137. Single Number II (medium)

class Solution:
    def singleNumber(self, nums: List[int]) -> int:
        counter = Counter(nums)
        for key in counter.keys():
            if counter[key] == 1:
                return key
        return -1

2461. Maximum Sum of Distinct Subarrays With Length K (medium)

TLE : 66/92

class Solution:
    def maximumSubarraySum(self, nums: List[int], k: int) -> int:
        n = len(nums)
        counter = Counter(nums[:k])
        num = sum(nums[:k])
        def check(p):
            count = 0
            for key in p.keys():
                if p[key] == 1:
                    count += 1
                if p[key] > 1:
                    return False
            return count == k

        res = num if check(counter) else 0
        for i in range(n - k):
            counter[nums[i]] -= 1
            num -= nums[i]
            counter[nums[i + k]] += 1
            num += nums[i + k]

            res = max(res, num if check(counter) else 0)

        return res

다른 카운팅 방식을 이용.

from collections import Counter

class Solution:
    def maximumSubarraySum(self, nums: List[int], k: int) -> int:
        n = len(nums)
        s = 0
        res = 0
        ctr = Counter()
        l = 0
        for i in range(n):
            s += nums[i]
            if ctr[nums[i]] == 0:
                l += 1
            ctr[nums[i]] += 1
            if i >= k:
                s -= nums[i - k]
                ctr[nums[i - k]] -= 1
                if ctr[nums[i - k]] == 0:
                    l -= 1
            if i >= k - 1:
                if l == k:
                    res = max(res, s)
        return res