Task Scheduler

TaskScheduler.java

public int leastInterval(char[] tasks, int n) {
    int[] counter = new int[26];
    int max = 0;  // 最多的字母的频数
    int maxCount = 0;  // 有几个这样子的字母
    for(char task : tasks) {
        counter[task - 'A']++;
        if(max == counter[task - 'A']) {
            maxCount++;
        }
        else if(max < counter[task - 'A']) {
            max = counter[task - 'A'];
            maxCount = 1;
        }
    }

    int segmentCount = max - 1;
    int segmentEmptySlots = n + 1 - maxCount;
    int emptySlots = segmentCount * segmentEmptySlots;
    int remainingTasks = tasks.length - max * maxCount;

    // 最难想的是最后两句
    int idles = Math.max(0, emptySlots - remainingTasks);

    return tasks.length + idles;
}