관심있는것들

First Missing Positive

https://leetcode.com/problems/first-missing-positive/description/class Solution: def firstMissingPositive(self, A: List[int]) -> int: for i in range(len(A)): if A[i] 0: A[val -1] *= -1 elif A[val -1] == 0: A[val-1] = -1 * (len(A) + 1) for i in range(1, len(A) + 1): if A[i - 1] >= 0: return..

Non-decreasing Array

https://leetcode.com/problems/non-decreasing-array/ class Solution: def checkPossibility(self, nums: List[int]) -> bool: changed = False for i in range(len(nums) - 1): if nums[i] = nums[i-1]: nums[i] = nums[i+1] else: nums[i+1] = nums[i] changed = True return Truewhen considering pair, we can either adjust lef..

Range Sum Query 2D - Immutable

https://leetcode.com/problems/range-sum-query-2d-immutable/class NumMatrix: def __init__(self, matrix: List[List[int]]): ROWS, COLS = len(matrix) , len(matrix[0]) self.sumMat = [[0] * (COLS + 1) for c in range(ROWS+1)] for r in range(ROWS): prefix = 0 for c in range(COLS): prefix += matrix[r][c] above = self.sumMat[r][c+..

https://leetcode.com/problems/check-if-a-string-contains-all-binary-codes-of-size-k/ class Solution: def hashAllCodes(self, s: str, k: int) -> bool: codeSet = set() for i in range(len(s) -k + 1): codeSet.add(s[i:i + k]) return len(codeSet) == 2 ** kA naive approach would be to iterate over the string for each given binary combination. But instead, we can use a ..

https://leetcode.com/problems/insert-delete-getrandom-o1/ class RandomizedSet: def __init__(self): self.numMap = {} self.numList = [] def insert(self, val: int) -> bool: res = val not in self.numMap if res: self.numMap[val] = len(self.numList) self.numList.append(val) return res def remove(self, val: int) -> bool: res = val..

https://leetcode.com/problems/repeated-dna-sequences/class Solution: def findRepeatedDnaSequences(self, s: str) -> List[str]: seen, res = set(), set() for l in range(len(s) - 9): cur = s[l: l+10] if cur in seen: res.add(cur) else: seen.add(cur) return list(res)10개의 substring이 set에있는지 쭉 확인하면서 given string itera..