229. Majority Element II
Description
Given an integer array of size n, find all elements that appear more than ⌊ n/3 ⌋ times.
Example 1:
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| Input: nums = [3,2,3]
Output: [3]
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Example 2:
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| Input: nums = [1]
Output: [1]
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Example 3:
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| Input: nums = [1,2]
Output: [1,2]
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Constraints:
1 <= nums.length <= 5 * 10^4-10^9 <= nums[i] <= 10^9
Follow up: Could you solve the problem in linear time and in O(1) space?
Hints/Notes
Solution
Language: C++
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| class Solution {
public:
vector<int> majorityElement(vector<int>& nums) {
int n = nums.size();
int mx1 = INT_MIN, mx2 = INT_MIN, count1 = 0, count2 = 0;
for (int num : nums) {
if (num == mx1) {
count1++;
} else if (num == mx2) {
count2++;
} else if (count1 == 0) {
mx1 = num;
count1++;
} else if (count2 == 0) {
mx2 = num;
count2++;
} else {
count1--;
count2--;
}
}
count1 = 0; count2 = 0;
for (int num : nums) {
if (num == mx1) {
count1++;
} else if (num == mx2) {
count2++;
}
}
vector<int> res;
if (count1 > n / 3) res.push_back(mx1);
if (count2 > n / 3) res.push_back(mx2);
return res;
}
};
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