{ "data": { "question": { "questionId": "2761", "questionFrontendId": "2626", "boundTopicId": null, "title": "Array Reduce Transformation", "titleSlug": "array-reduce-transformation", "content": "

Given an integer array nums, a reducer function fn, and an initial value init, return a reduced array.

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A 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.

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If the length of the array is 0, it should return init.

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Please solve it without using the built-in Array.reduce method.

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Example 1:

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\nInput: \nnums = [1,2,3,4]\nfn = function sum(accum, curr) { return accum + curr; }\ninit = 0\nOutput: 10\nExplanation:\ninitially, the value is init=0.\n(0) + nums[0] = 1\n(1) + nums[1] = 3\n(3) + nums[2] = 6\n(6) + nums[3] = 10\nThe final answer is 10.\n
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Example 2:

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\nInput: \nnums = [1,2,3,4]\nfn = function sum(accum, curr) { return accum + curr * curr; }\ninit = 100\nOutput: 130\nExplanation:\ninitially, the value is init=100.\n(100) + nums[0]^2 = 101\n(101) + nums[1]^2 = 105\n(105) + nums[2]^2 = 114\n(114) + nums[3]^2 = 130\nThe final answer is 130.\n
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Example 3:

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\nInput: \nnums = []\nfn = function sum(accum, curr) { return 0; }\ninit = 25\nOutput: 25\nExplanation: For empty arrays, the answer is always init.\n
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Constraints:

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Node.js 16.13.2.

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Your code is run with --harmony flag, enabling new ES6 features.

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lodash.js library is included by default.

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For Priority Queue / Queue data structures, you may use 5.3.0 version of datastructures-js/priority-queue and 4.2.1 version of datastructures-js/queue.

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TypeScript 5.1.6, Node.js 16.13.2.

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Your code is run with --harmony flag, enabling new ES2022 features.

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lodash.js library is included by default.

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