Easy
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:
Input: nums = [3,2,3]
Output: 3
Example 2:
Input: nums = [2,2,1,1,1,2,2]
Output: 2
Constraints:
n == nums.length
1 <= n <= 5 * 104
-231 <= nums[i] <= 231 - 1
Follow-up: Could you solve the problem in linear time and in O(1)
space?
class Solution {
func majorityElement(_ arr: [Int]) -> Int {
var count = 1
var majority = arr[0]
// For Potential Majority Element
for i in 1..<arr.count {
if arr[i] == majority {
count += 1
} else {
if count > 1 {
count -= 1
} else {
majority = arr[i]
}
}
}
// For Confirmation
count = 0
for num in arr {
if num == majority {
count += 1
}
}
return count >= (arr.count / 2) + 1 ? majority : -1
}
}