Array Reduce Transformation Without Built-In Method
In this lab, you will be implementing a custom reduce
function for integer arrays, without using the built-in Array.reduce
method. The custom reduce
function takes an integer array nums
, a reducer function fn
, and an initial value init
as arguments and returns the reduced array value.
The reduced array is created by applying the following operation: val = fn(init, nums[0])
, val = fn(val, nums[1])
, val = fn(val, nums[2])
, until every element in the array has been processed. The final value of val
is returned.
If the length of the array is 0, the function should return the init
value.
Example
Consider the following examples to get a better understanding of the reduce
function:
Example 1:
Input:
nums = [1, 2, 3, 4] fn = function sum(accum, curr) { return accum + curr; } init = 0
Output: 10
Explanation:
- Initially, the value is
init=0
. (0) + nums[0] = 1
(1) + nums[1] = 3
(3) + nums[2] = 6
(6) + nums[3] = 10
- The final answer is
10
.
Example 2:
Input:
nums = [1, 2, 3, 4] fn = function sum(accum, curr) { return accum + curr * curr; } init = 100
Output: 130
Explanation:
- Initially, the value is
init=100
. (100) + nums[0]^2 = 101
(101) + nums[1]^2 = 105
(105) + nums[2]^2 = 114
(114) + nums[3]^2 = 130
- The final answer is
130
.
Example 3:
Input:
nums = [] fn = function sum(accum, curr) { return 0; } init = 25
Output: 25
Explanation: For empty arrays, the answer is always init
.
Constraints
0 <= nums.length <= 1000
0 <= nums[i] <= 1000
0 <= init <= 1000
Now that you've understood the problem statement, go ahead and complete the lab by writing the appropriate code and completing the challenges. Good luck!