Third Maximum Number
Given a non-empty array of integers, return the third maximum number in this array. If it does not exist, return the maximum number. The time complexity must be in O(n).
Example 1:
Input: [3, 2, 1] Output: 1 Explanation: The third maximum is 1.
Example 2:
Input: [1, 2] Output: 2 Explanation: The third maximum does not exist, so the maximum (2) is returned instead.
Example 3:
Input: [2, 2, 3, 1] Output: 1 Explanation: Note that the third maximum here means the third maximum distinct number. Both numbers with value 2 are both considered as second maximum.
1 class Solution { 2 public: 3 int thirdMax(vector<int>& nums) { 4 set<int> container; 5 for (int number : nums) { 6 container.insert(number); 7 } 8 9 auto ite = container.rbegin(); 10 if (container.size() < 3) return *ite; 11 ite++; ite++; 12 return *ite; 13 } 14 };