leetcode-problemset/leetcode/originData/array-reduce-transformation.json

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            "questionId": "2761",
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            "title": "Array Reduce Transformation",
            "titleSlug": "array-reduce-transformation",
            "content": "<p>Given an integer array&nbsp;<code>nums</code>, a reducer function&nbsp;<code>fn</code>, and an initial value&nbsp;<code>init</code>, return a&nbsp;<strong>reduced</strong>&nbsp;array.</p>\n\n<p>A&nbsp;<strong>reduced</strong>&nbsp;array is created by applying the following operation:&nbsp;<code>val = fn(init, nums[0])</code>, <code>val&nbsp;= fn(val, nums[1])</code>,&nbsp;<code>val&nbsp;= fn(val, nums[2])</code>,&nbsp;<code>...</code>&nbsp;until every element in the array has been processed. The final value of&nbsp;<code>val</code>&nbsp;is returned.</p>\n\n<p>If the length of the array is 0, it should return&nbsp;<code>init</code>.</p>\n\n<p>Please solve it without using the built-in <code>Array.reduce</code> method.</p>\n\n<p>&nbsp;</p>\n<p><strong class=\"example\">Example 1:</strong></p>\n\n<pre>\n<strong>Input:</strong> \nnums = [1,2,3,4]\nfn = function sum(accum, curr) { return accum + curr; }\ninit = 0\n<strong>Output:</strong> 10\n<strong>Explanation:</strong>\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</pre>\n\n<p><strong class=\"example\">Example 2:</strong></p>\n\n<pre>\n<strong>Input:</strong> \nnums = [1,2,3,4]\nfn = function sum(accum, curr) { return accum + curr * curr; }\ninit = 100\n<strong>Output:</strong> 130\n<strong>Explanation:</strong>\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</pre>\n\n<p><strong class=\"example\">Example 3:</strong></p>\n\n<pre>\n<strong>Input:</strong> \nnums = []\nfn = function sum(accum, curr) { return 0; }\ninit = 25\n<strong>Output:</strong> 25\n<strong>Explanation:</strong> For empty arrays, the answer is always init.\n</pre>\n\n<p>&nbsp;</p>\n<p><strong>Constraints:</strong></p>\n\n<ul>\n\t<li><code>0 &lt;= nums.length &lt;= 1000</code></li>\n\t<li><code>0 &lt;= nums[i] &lt;= 1000</code></li>\n\t<li><code>0 &lt;= init &lt;= 1000</code></li>\n</ul>\n",
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                    "code": "/**\n * @param {number[]} nums\n * @param {Function} fn\n * @param {number} init\n * @return {number}\n */\nvar reduce = function(nums, fn, init) {\n    \n};",
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                    "code": "type Fn = (accum: number, curr: number) => number\n\nfunction reduce(nums: number[], fn: Fn, init: number): number {\n    \n};",
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            "hints": [
                "Declare a variable \"res\" and set it it equal to the initial value.",
                "Loop over each value in the array and set \"res\" = fn(res, arr[i])."
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