完成所有任务需要的最少轮数

/*
 * Solution using Java Stream API
 * 
 * This approach uses the same logic as the standard Java solution but leverages Java Streams to handle
 * the collection and counting of task frequencies.
 */
import java.util.Arrays;
import java.util.Map;
import java.util.stream.Collectors;

public class TaskSchedulerStream {
    public int minRounds(int[] tasks) {
        // Count the frequency of each difficulty level using Streams
        Map<Integer, Long> frequencyMap = Arrays.stream(tasks)
                .boxed()
                .collect(Collectors.groupingBy(task -> task, Collectors.counting()));
        // Calculate the minimum rounds needed
        int rounds = 0;
        for (long freq : frequencyMap.values()) {
            if (freq == 1) {
                return -1; // Impossible to complete
            }
            rounds += (freq + 2) / 3; // Minimum rounds needed to cover freq tasks
        }
        return rounds;
    }
}