Question

Please write in Java and Array list.

3 THE COUNT LIKE PROBLEM

Start with 1 String array wordList and one String word. Your method should calculate and return the number of times that word appears in the array wordList.

countLike({"a", "a", "b", "c"}, "a") → 2

countLike({"a", "a", "b", "c"}, "c") → 1

countLike({"a", "a", "b", "c"}, "3") → 0

4 THE AVERAGE EVENS PROBLEM

Start with an int array named nums. Return the average of all the even numbers in the array. A number (n) is even if n % 2 == 0. If there are no even numbers in the array, return -1.

averageEvens({1, 2, 3}) → 2.0

averageEvens({1, 5}) → -1.0

averageEvens({2, 3, 4}) → 3.0

Answer 1

// 3
public int countLike(ArrayList<String> arr, String word) {
    int count = 0;
    for (int i = 0; i < arr.size(); i++) {
        if (arr.get(i).equals(word))
            ++count;
    }
    return count;
}

// 4
public double averageEvens(ArrayList<Integer> nums) {
    double sum = 0, count = 0;
    for (int i = 0; i < nums.size(); i++) {
        if (nums.get(i) % 2 == 0) {
            sum += nums.get(i);
            ++count;
        }
    }
    if (count == 0)
        return -1;
    else
        return sum/count;
}