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任务调度器

2022/10/11

https://leetcode.cn/problems/task-scheduler/

示例​

示例一​

输入：tasks = ["A","A","A","B","B","B"], n = 2
输出：8
解释：A -> B -> (待命) -> A -> B -> (待命) -> A -> B
     在本示例中，两个相同类型任务之间必须间隔长度为 n = 2 的冷却时间，而执行一个任务只需要一个单位时间，所以中间出现了（待命）状态。

示例二​

输入：tasks = ["A","A","A","B","B","B"], n = 0
输出：6
解释：在这种情况下，任何大小为 6 的排列都可以满足要求，因为 n = 0
["A","A","A","B","B","B"]
["A","B","A","B","A","B"]
["B","B","B","A","A","A"]
...
诸如此类

示例三​

输入：tasks = ["A","A","A","A","A","A","B","C","D","E","F","G"], n = 2
输出：16
解释：一种可能的解决方案是：
     A -> B -> C -> A -> D -> E -> A -> F -> G -> A -> (待命) -> (待命) -> A -> (待命) -> (待命) -> A

题解​

构造​

var leastInterval = function(tasks, n) {
    const freq = _.countBy(tasks);

    // 最多的执行次数
    const maxExec = Math.max(...Object.values(freq));
    // 具有最多执行次数的任务数量
    let maxCount = 0;
    Object.values(freq).forEach(v => {
        if (v === maxExec) {
            maxCount++;
        }
    })

    return Math.max((maxExec - 1) * (n + 1) + maxCount, tasks.length);
};