#287

Find the Duplicate Number

medium· Linked Listruns: 0

Given an array of integers nums containing n + 1 integers where each integer is in the range [1, n] inclusive, there is exactly one repeated number. Return the repeated number. The algorithm must use only constant extra space and may not modify the input array.

wpm 0acc 100%time 0:000 / 371

class Solution:
    def findDuplicate(self, nums: list[int]) -> int:
        slow = fast = nums[0]
        while True:
            slow = nums[slow]
            fast = nums[nums[fast]]
            if slow == fast:
                break
        slow2 = nums[0]
        while slow != slow2:
            slow = nums[slow]
            slow2 = nums[slow2]
        return slow

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