如何在 java 中不定义大小的情况下获取 N 个元素的输入数组

Question

Input: In the input, there will be an array of N element

Output: Output will be the number that is the sum of its left and right sub-arrays.

Example Input: 2 3 5 20 5 3 2

Output: 20

Input: 5 10 20 122 30 12 9 36

Output: 122

Anyone can explain this question how it will be solved as I am applying logic as the output will be the middle element of the array but is this true logic. Also, for increasing the size of an array at runtime we can use ArrayList but how it will be declared can anyone suggest code. Thank you.

Answer 1

You basically need to find the element which is equals to the sum of its right and left elements. Below program should achieve the same.

public class Sample {
    public static void main(String[] args) {
        int arr[] = { 5, 10, 20, 122, 30, 12, 9, 36 };
        for (int i = 0; i < arr.length; i++) {
            int temp = arr[i];
            int sum = 0;
            if (i == 0) {
                // first element simple sum the right elements
                for (int j = i + 1; j < arr.length; j++) {
                    sum += arr[j];

                }

            } else {
                // sum the right elements
                for (int j = i + 1; j < arr.length; j++) {
                    sum += arr[j];

                }
                // sum the left elements
                for (int j = i - 1; j >= 0; j--) {
                    sum += arr[j];

                }
                // check if sum of left and right elements equals element.
                if (sum == arr[i]) {
                    System.out.println(arr[i]);
                    break;
                }
            }

        }

    }
}

Answer 2

i think you have to just calc the total sum and subtract every number from it in array and when after substraction of ith no from total sum gives again that ith number means this number is equal to sum of all other right and left subarray

l=list(map(int,input().split(' ')))
x=sum(l)
y=0

for i in range(len(l)):
    y=x-l[i]
    if(y==l[i]):
        print(l[i])
        break;