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"content": "<p>You are given a <strong>0-indexed</strong> array of positive integers <code>w</code> where <code>w[i]</code> describes the <strong>weight</strong> of the <code>i<sup>th</sup></code> index.</p>\n\n<p>You need to implement the function <code>pickIndex()</code>, which <strong>randomly</strong> picks an index in the range <code>[0, w.length - 1]</code> (<strong>inclusive</strong>) and returns it. The <strong>probability</strong> of picking an index <code>i</code> is <code>w[i] / sum(w)</code>.</p>\n\n<ul>\n\t<li>For example, if <code>w = [1, 3]</code>, the probability of picking index <code>0</code> is <code>1 / (1 + 3) = 0.25</code> (i.e., <code>25%</code>), and the probability of picking index <code>1</code> is <code>3 / (1 + 3) = 0.75</code> (i.e., <code>75%</code>).</li>\n</ul>\n\n<p> </p>\n<p><strong>Example 1:</strong></p>\n\n<pre>\n<strong>Input</strong>\n["Solution","pickIndex"]\n[[[1]],[]]\n<strong>Output</strong>\n[null,0]\n\n<strong>Explanation</strong>\nSolution solution = new Solution([1]);\nsolution.pickIndex(); // return 0. The only option is to return 0 since there is only one element in w.\n</pre>\n\n<p><strong>Example 2:</strong></p>\n\n<pre>\n<strong>Input</strong>\n["Solution","pickIndex","pickIndex","pickIndex","pickIndex","pickIndex"]\n[[[1,3]],[],[],[],[],[]]\n<strong>Output</strong>\n[null,1,1,1,1,0]\n\n<strong>Explanation</strong>\nSolution solution = new Solution([1, 3]);\nsolution.pickIndex(); // return 1. It is returning the second element (index = 1) that has a probability of 3/4.\nsolution.pickIndex(); // return 1\nsolution.pickIndex(); // return 1\nsolution.pickIndex(); // return 1\nsolution.pickIndex(); // return 0. It is returning the first element (index = 0) that has a probability of 1/4.\n\nSince this is a randomization problem, multiple answers are allowed.\nAll of the following outputs can be considered correct:\n[null,1,1,1,1,0]\n[null,1,1,1,1,1]\n[null,1,1,1,0,0]\n[null,1,1,1,0,1]\n[null,1,0,1,0,0]\n......\nand so on.\n</pre>\n\n<p> </p>\n<p><strong>Constraints:</strong></p>\n\n<ul>\n\t<li><code>1 <= w.length <= 10<sup>4</sup></code></li>\n\t<li><code>1 <= w[i] <= 10<sup>5</sup></code></li>\n\t<li><code>pickIndex</code> will be called at most <code>10<sup>4</sup></code> times.</li>\n</ul>\n",
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"code": "class Solution {\npublic:\n Solution(vector<int>& w) {\n \n }\n \n int pickIndex() {\n \n }\n};\n\n/**\n * Your Solution object will be instantiated and called as such:\n * Solution* obj = new Solution(w);\n * int param_1 = obj->pickIndex();\n */",
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"code": "class Solution(object):\n\n def __init__(self, w):\n \"\"\"\n :type w: List[int]\n \"\"\"\n \n\n def pickIndex(self):\n \"\"\"\n :rtype: int\n \"\"\"\n \n\n\n# Your Solution object will be instantiated and called as such:\n# obj = Solution(w)\n# param_1 = obj.pickIndex()",
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"code": "class Solution:\n\n def __init__(self, w: List[int]):\n \n\n def pickIndex(self) -> int:\n \n\n\n# Your Solution object will be instantiated and called as such:\n# obj = Solution(w)\n# param_1 = obj.pickIndex()",
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"code": "public class Solution {\n\n public Solution(int[] w) {\n \n }\n \n public int PickIndex() {\n \n }\n}\n\n/**\n * Your Solution object will be instantiated and called as such:\n * Solution obj = new Solution(w);\n * int param_1 = obj.PickIndex();\n */",
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"code": "/**\n * @param {number[]} w\n */\nvar Solution = function(w) {\n \n};\n\n/**\n * @return {number}\n */\nSolution.prototype.pickIndex = function() {\n \n};\n\n/** \n * Your Solution object will be instantiated and called as such:\n * var obj = new Solution(w)\n * var param_1 = obj.pickIndex()\n */",
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"code": "class Solution(w: IntArray) {\n\n fun pickIndex(): Int {\n \n }\n\n}\n\n/**\n * Your Solution object will be instantiated and called as such:\n * var obj = Solution(w)\n * var param_1 = obj.pickIndex()\n */",
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