Question

2695. Array Wrapper

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Description

Create a class ArrayWrapper that accepts an array of integers in its constructor. This class should have two features:

• When two instances of this class are added together with the + operator, the resulting value is the sum of all the elements in both arrays.
• When the String() function is called on the instance, it will return a comma separated string surrounded by brackets. For example, [1,2,3].

 

Example 1:

Input: nums = [[1,2],[3,4]], operation = "Add"
Output: 10
Explanation:
const obj1 = new ArrayWrapper([1,2]);
const obj2 = new ArrayWrapper([3,4]);
obj1 + obj2; // 10

Example 2:

Input: nums = [[23,98,42,70]], operation = "String"
Output: "[23,98,42,70]"
Explanation:
const obj = new ArrayWrapper([23,98,42,70]);
String(obj); // "[23,98,42,70]"

Example 3:

Input: nums = [[],[]], operation = "Add"
Output: 0
Explanation:
const obj1 = new ArrayWrapper([]);
const obj2 = new ArrayWrapper([]);
obj1 + obj2; // 0

 

Constraints:

• 0 <= nums.length <= 1000
• 0 <= nums[i] <= 1000
• Note: nums is the array passed to the constructor

Solutions

Solution 1

class ArrayWrapper {
  private nums: number[];
  private s: number;

  constructor(nums: number[]) {
    this.nums = nums;
    this.s = nums.reduce((a, b) => a + b, 0);
  }

  valueOf() {
    return this.s;
  }

  toString() {
    return `[${this.nums}]`;
  }
}

/**
 * const obj1 = new ArrayWrapper([1,2]);
 * const obj2 = new ArrayWrapper([3,4]);
 * obj1 + obj2; // 10
 * String(obj1); // "[1,2]"
 * String(obj2); // "[3,4]"
 */