2244.minimum-rounds-to-complete-all-tasks.cpp

/*
 * @lc app=leetcode id=2244 lang=cpp
 *
 * [2244] Minimum Rounds to Complete All Tasks
 *
 * https://leetcode.com/problems/minimum-rounds-to-complete-all-tasks/description/
 *
 * algorithms
 * Medium (57.81%)
 * Likes:    757
 * Dislikes: 19
 * Total Accepted:    42.1K
 * Total Submissions: 69.1K
 * Testcase Example:  '[2,2,3,3,2,4,4,4,4,4]'
 *
 * You are given a 0-indexed integer array tasks, where tasks[i] represents the
 * difficulty level of a task. In each round, you can complete either 2 or 3
 * tasks of the same difficulty level.
 *
 * Return the minimum rounds required to complete all the tasks, or -1 if it is
 * not possible to complete all the tasks.
 *
 *
 * Example 1:
 *
 *
 * Input: tasks = [2,2,3,3,2,4,4,4,4,4]
 * Output: 4
 * Explanation: To complete all the tasks, a possible plan is:
 * - In the first round, you complete 3 tasks of difficulty level 2.
 * - In the second round, you complete 2 tasks of difficulty level 3.
 * - In the third round, you complete 3 tasks of difficulty level 4.
 * - In the fourth round, you complete 2 tasks of difficulty level 4.
 * It can be shown that all the tasks cannot be completed in fewer than 4
 * rounds, so the answer is 4.
 *
 *
 * Example 2:
 *
 *
 * Input: tasks = [2,3,3]
 * Output: -1
 * Explanation: There is only 1 task of difficulty level 2, but in each round,
 * you can only complete either 2 or 3 tasks of the same difficulty level.
 * Hence, you cannot complete all the tasks, and the answer is -1.
 *
 *
 *
 * Constraints:
 *
 *
 * 1 <= tasks.length <= 10^5
 * 1 <= tasks[i] <= 10^9
 *
 *
 */

// @lc code=start
// #include <bits/stdc++.h>
// using namespace std;
class Solution
{
public:
    int minimumRounds(vector<int> &tasks)
    {
        int res = 0;
        unordered_map<int, float> freqMap;
        for (int x : tasks)
            freqMap[x]++;
        for (auto freqPair : freqMap)
        {
            if (freqPair.second == 1)
                return -1;
            res += ceil(freqPair.second / 3);
        }
        return res;
    }
};
// @lc code=end