帮我完成以下代码。We define a runs in a list is a series of 2 or more adjacent elements of the same value. Write a method to return the number of runs in the input list. Test case 1: countRuns([1, 2, 2, 2, 3]) = 1 (which is 2, 2, 2) Test case 2: countRuns([1, 1, 2, 3, 4, 5, 5]) = 2 (which is 1, 1; and 5, 5). public static int countRuns(List<Integer> list) {}

public static int countRuns(List<Integer> list) {
    int count = 0;
    int currentRun = 1;
    for (int i = 1; i < list.size(); i++) {
        if (list.get(i).equals(list.get(i-1))) {
            currentRun++;
        } else {
            if (currentRun >= 2) {
                count++;
            }
            currentRun = 1; // reset current run
        }
    }
    if (currentRun >= 2) {
        count++;
    }
    return count;
}

这个方法遍历列表，计算连续相同元素的长度。如果这个长度大于等于2，就将计数器加1。最后返回计数器的值。

相关问题

We will write a procedure every-nth that accepts two arguments: num is an integer and list-of-sents is a list of a certain number of lists. every-nth selects the num-th elements from each list in list-of-sents and returns the list of selected elements. Assume that all lists in listof-sents have more than num elements. Consider the first element as the 0-th. Examples: (every-nth 2 '((a b c d) (e f g h))) gives (c g). (every-nth 1 '((a b c) (d e f) (g h i))) gives (b e h). (define (every-nth num list-of-sents) ; You must fill in this part )

Here's one way to implement the `every-nth` procedure:

(define (every-nth num list-of-sents)
  (apply map
         (lambda args (list-ref args num))
         list-of-sents))

In this implementation, we use `map` to apply a function to each element of `list-of-sents`. The function we apply is a lambda that takes `num` arguments (one from each sublist) and returns the `num`-th element of the sublist. We use `apply` to pass the sublists as separate arguments to `map`.

Note that we assume that all sublists have at least `num+1` elements, since we count the first element as the 0-th. If some sublists might have fewer elements, we should add a check to avoid an index out of bounds error.