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LeetCode 169 Majority Element

LeetCode

<div>

Given an array nums of size n, return the majority element.

The majority element is the element that appears more than ⌊n / 2⌋ times. You may assume that the majority element always exists in the array.

Example 1:

<pre>Input: nums = [3,2,3] Output: 3 </pre>

Example 2:

<pre>Input: nums = [2,2,1,1,1,2,2] Output: 2 </pre>

Constraints:

  • n == nums.length
  • 1 <= n <= 5 * 10<sup>4</sup>
  • -2<sup>31</sup> <= nums[i] <= 2<sup>31</sup> - 1

Follow-up: Could you solve the problem in linear time and in O(1) space?</div>

题目大意:

求数组中的众数

解题思路:

编程之美的水王法

解题步骤:

N/A

注意事项:

Python代码:

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def majorityElement(self, nums: List[int]) -> int:
candidate, count = 0, 0
for i in range(len(nums)):
if count == 0:
candidate = nums[i]
count += 1
continue
if nums[i] == candidate:
count += 1
else:
count -= 1
return candidate

算法分析:

时间复杂度为O(n),空间复杂度O(1)

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