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hi-rachel.py
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38 lines (32 loc) · 736 Bytes
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"""
TC: O(n)
SC: O(n)
"""
from typing import List
class Solution:
def missingNumber(self, nums: List[int]) -> int:
num_set = set(nums)
for i in range(len(nums)):
if i not in num_set:
return i
return len(nums)
"""
TC: O(n log n)
SC: O(1)
"""
class Solution:
def missingNumber(self, nums: List[int]) -> int:
nums.sort()
for idx, num in enumerate(nums):
if idx != num:
return idx
return len(nums)
"""
TC: O(n)
SC: O(1)
"""
class Solution:
def missingNumber(self, nums: List[int]) -> int:
expected_sum = len(nums) * (len(nums) + 1) // 2
actual_sum = sum(nums)
return expected_sum - actual_sum