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"title": "Array Reduce Transformation",
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"content": "<p>Given an integer array <code>nums</code>, a reducer function <code>fn</code>, and an intial value <code>init</code>, return a <strong>reduced</strong> array.</p>\n\n<p>A <strong>reduced</strong> array is created by applying the following operation: <code>val = fn(init, nums[0])</code>, <code>val = fn(val, nums[1])</code>, <code>val = fn(val, arr[2])</code>, <code>...</code> until every element in the array has been processed. The final value of <code>val</code> is returned.</p>\n\n<p>If the length of the array is 0, it should return <code>init</code>.</p>\n\n<p>Please solve it without using the built-in <code>Array.reduce</code> method.</p>\n\n<p> </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> </p>\n<p><strong>Constraints:</strong></p>\n\n<ul>\n\t<li><code>0 <= nums.length <= 1000</code></li>\n\t<li><code>0 <= nums[i] <= 1000</code></li>\n\t<li><code>0 <= init <= 1000</code></li>\n</ul>\n",
"translatedTitle": "数组归约运算",
"translatedContent": "<p>请你编写一个函数，它的参数为一个整数数组 <code>nums</code> 、一个计算函数 <code>fn</code> 和初始值 <font color=\"#c7254e\"><font face=\"Menlo, Monaco, Consolas, Courier New, monospace\"><span style=\"font-size:12.6px\"><span style=\"background-color:#f9f2f4\">init </span></span></font></font>。返回一个数组 <strong>归约后 </strong>的值。</p>\n\n<p>你可以定义一个数组 <strong>归约后 </strong>的值，然后应用以下操作： <code>val = fn(init, nums[0])</code> ， <code>val = fn(val, nums[1])</code> ， <code>val = fn(val, arr[2])</code> ，<code>...</code> 直到数组中的每个元素都被处理完毕。返回 <code>val</code> 的最终值。</p>\n\n<p>如果数组的长度为 0，它应该返回 <code>init</code> 的值。</p>\n\n<p>请你在不使用内置数组方法的 <code>Array.reduce</code> 前提下解决这个问题。</p>\n\n<p> </p>\n\n<p><strong class=\"example\">示例 1：</strong></p>\n\n<pre>\n<strong>输入：</strong>\nnums = [1,2,3,4]\nfn = function sum(accum, curr) { return accum + curr; }\ninit = 0\n<strong>输出：</strong>10\n<strong>解释：</strong>\n初始值为 init=0 。\n(0) + nums[0] = 1\n(1) + nums[1] = 3\n(3) + nums[2] = 6\n(6) + nums[3] = 10\nVal 最终值为 10。\n</pre>\n\n<p><strong class=\"example\">示例 2：</strong></p>\n\n<pre>\n<strong>输入：</strong> \nnums = [1,2,3,4]\nfn = function sum(accum, curr) { return accum + curr * curr; }\ninit = 100\n<strong>输出：</strong>130\n<strong>解释：</strong>\n初始值为 init=0 。\n(100) + nums[0]^2 = 101\n(101) + nums[1]^2 = 105\n(105) + nums[2]^2 = 114\n(114) + nums[3]^2 = 130\nVal 最终值为 130。\n</pre>\n\n<p><strong class=\"example\">示例3:</strong></p>\n\n<pre>\n<strong>输入：</strong> \nnums = []\nfn = function sum(accum, curr) { return 0; }\ninit = 25\n<strong>输出：</strong>25\n<b>解释：</b>这是一个空数组，所以返回 init 。\n</pre>\n\n<p> </p>\n\n<p><strong>提示：</strong></p>\n\n<ul>\n\t<li><code>0 <= nums.length <= 1000</code></li>\n\t<li><code>0 <= nums[i] <= 1000</code></li>\n\t<li><code>0 <= init <= 1000</code></li>\n</ul>\n",
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