数组的和与乘（在java中）

Question

At first, the witch had 8 dolls with the following number of elements: {-1, 1, 2, 3, 5, 5, 3, 7}
After the first night, the dolls were merged into 4 with the following number of elements: {0, 5, 10, 10}
After the second night, the 4 dolls were merged into two with the following number of elements: {0, 100}
After the third night, the last 2 dolls were merged into one with 100 elements

只剩下一个嵌套娃娃了，我们有我们的答案：100个。输入/输出

[input] array.integer nestingDollsElements

Number of dolls, 1 ≤ n ≤ 27

Number of elements of each doll, -100 ≤ nestingDollsElements[i] ≤ 100

[output] integer

The number of elements of the last nesting doll.

我已经开始像这样解决它，但我不确定是否需要将这个数组的每两个元素的和复制到新的数组中，以及如何循环。同样，这个循环提供了每个连续元素的和，而不是每对元素的和。很抱歉问了这么愚蠢的问题，如果有人愿意帮忙，我将非常感谢。

public static int getLastNestingDoll (int[] nestingDollsElements) {
    int sum = 0;
    
    if (nestingDollsElements.length % 2 == 0 ) {
                
        for (int i = 0; i  < nestingDollsElements.length; i++) {                
            sum = (nestingDollsElements[i] + nestingDollsElements[i + 1]);              
            System.out.println(sum + " ");              
        }   
    }
    else   { System.out.println("The array is not even"); }     

    return sum;
}

Answer 1

我不确定是否需要将这个数组的每两个元素的和复制到新的数组中，以及如何循环

是的，合并意味着应该用初始数组的一半大小创建一个新数组，直到合并数组的长度为奇数。

示例实现：

static int[] merge(int ... arr) {
    boolean add = true; // flag to define the function applied while merging
    while (arr.length % 2 == 0) {
        int[] merged = new int[arr.length / 2]; // half of input array
        for (int i = 0, j = 0; i < merged.length; i++, j += 2) {
            merged[i] = add ? arr[j] + arr[j + 1] : arr[j] * arr[j + 1];
        }
        add = !add;
        arr = merged;
    }
    return arr;
}

public static Integer singleNum(int ... arr) {
    if (Integer.bitCount(arr.length) == 1) {
        return merge(arr)[0];
    } else if (Integer.bitCount(arr.length) == 0) {
        return 0; // empty array, nothing to merge
    }
    System.out.println("The size of the input array is not even");
    return null;
}

System.out.println(singleNum(-1, 1, 2, 3, 5, 5, 3, 7));
// -> 100