FPEvalRepoPublic/LeetCodeMetaData

1{2  "id": 3699,3  "name": "count-special-subsequences",4  "difficulty": "Medium",5  "link": "https://leetcode.com/problems/count-special-subsequences/",6  "date": "2024-12-22",7  "task_description": "You are given an array `nums` consisting of positive integers. A **special subsequence** is defined as a subsequence of length 4, represented by indices `(p, q, r, s)`, where `p < q < r < s`. This subsequence **must** satisfy the following conditions: `nums[p] * nums[r] == nums[q] * nums[s]` There must be _at least_ **one** element between each pair of indices. In other words, `q - p > 1`, `r - q > 1` and `s - r > 1`. Return the _number_ of different **special** **subsequences** in `nums`. **Example 1:** **Input:** nums = [1,2,3,4,3,6,1] **Output:** 1 **Explanation:** There is one special subsequence in `nums`. `(p, q, r, s) = (0, 2, 4, 6)`: This corresponds to elements `(1, 3, 3, 1)`. `nums[p] * nums[r] = nums[0] * nums[4] = 1 * 3 = 3` `nums[q] * nums[s] = nums[2] * nums[6] = 3 * 1 = 3` **Example 2:** **Input:** nums = [3,4,3,4,3,4,3,4] **Output:** 3 **Explanation:** There are three special subsequences in `nums`. `(p, q, r, s) = (0, 2, 4, 6)`: This corresponds to elements `(3, 3, 3, 3)`. `nums[p] * nums[r] = nums[0] * nums[4] = 3 * 3 = 9` `nums[q] * nums[s] = nums[2] * nums[6] = 3 * 3 = 9` `(p, q, r, s) = (1, 3, 5, 7)`: This corresponds to elements `(4, 4, 4, 4)`. `nums[p] * nums[r] = nums[1] * nums[5] = 4 * 4 = 16` `nums[q] * nums[s] = nums[3] * nums[7] = 4 * 4 = 16` `(p, q, r, s) = (0, 2, 5, 7)`: This corresponds to elements `(3, 3, 4, 4)`. `nums[p] * nums[r] = nums[0] * nums[5] = 3 * 4 = 12` `nums[q] * nums[s] = nums[2] * nums[7] = 3 * 4 = 12` **Constraints:** `7 <= nums.length <= 1000` `1 <= nums[i] <= 1000`",8  "test_case": [9    {10      "label": "Example 1",11      "input": "nums = [1,2,3,4,3,6,1]",12      "output": "1 "13    },14    {15      "label": "Example 2",16      "input": "nums = [3,4,3,4,3,4,3,4]",17      "output": "3 "18    }19  ],20  "constraints": [21    "nums[p] * nums[r] == nums[q] * nums[s]",22    "There must be at least one element between each pair of indices. In other words, q - p > 1, r - q > 1 and s - r > 1.",23    "(p, q, r, s) = (0, 2, 4, 6):\n\n\t\nThis corresponds to elements (1, 3, 3, 1).\nnums[p] * nums[r] = nums[0] * nums[4] = 1 * 3 = 3\nnums[q] * nums[s] = nums[2] * nums[6] = 3 * 1 = 3",24    "This corresponds to elements (1, 3, 3, 1).",25    "nums[p] * nums[r] = nums[0] * nums[4] = 1 * 3 = 3",26    "nums[q] * nums[s] = nums[2] * nums[6] = 3 * 1 = 3",27    "This corresponds to elements (1, 3, 3, 1).",28    "nums[p] * nums[r] = nums[0] * nums[4] = 1 * 3 = 3",29    "nums[q] * nums[s] = nums[2] * nums[6] = 3 * 1 = 3",30    "(p, q, r, s) = (0, 2, 4, 6):\n\n\t\nThis corresponds to elements (3, 3, 3, 3).\nnums[p] * nums[r] = nums[0] * nums[4] = 3 * 3 = 9\nnums[q] * nums[s] = nums[2] * nums[6] = 3 * 3 = 9",31    "This corresponds to elements (3, 3, 3, 3).",32    "nums[p] * nums[r] = nums[0] * nums[4] = 3 * 3 = 9",33    "nums[q] * nums[s] = nums[2] * nums[6] = 3 * 3 = 9",34    "(p, q, r, s) = (1, 3, 5, 7):\n\t\nThis corresponds to elements (4, 4, 4, 4).\nnums[p] * nums[r] = nums[1] * nums[5] = 4 * 4 = 16\nnums[q] * nums[s] = nums[3] * nums[7] = 4 * 4 = 16",35    "This corresponds to elements (4, 4, 4, 4).",36    "nums[p] * nums[r] = nums[1] * nums[5] = 4 * 4 = 16",37    "nums[q] * nums[s] = nums[3] * nums[7] = 4 * 4 = 16",38    "(p, q, r, s) = (0, 2, 5, 7):\n\t\nThis corresponds to elements (3, 3, 4, 4).\nnums[p] * nums[r] = nums[0] * nums[5] = 3 * 4 = 12\nnums[q] * nums[s] = nums[2] * nums[7] = 3 * 4 = 12",39    "This corresponds to elements (3, 3, 4, 4).",40    "nums[p] * nums[r] = nums[0] * nums[5] = 3 * 4 = 12",41    "nums[q] * nums[s] = nums[2] * nums[7] = 3 * 4 = 12",42    "This corresponds to elements (3, 3, 3, 3).",43    "nums[p] * nums[r] = nums[0] * nums[4] = 3 * 3 = 9",44    "nums[q] * nums[s] = nums[2] * nums[6] = 3 * 3 = 9",45    "This corresponds to elements (4, 4, 4, 4).",46    "nums[p] * nums[r] = nums[1] * nums[5] = 4 * 4 = 16",47    "nums[q] * nums[s] = nums[3] * nums[7] = 4 * 4 = 16",48    "This corresponds to elements (3, 3, 4, 4).",49    "nums[p] * nums[r] = nums[0] * nums[5] = 3 * 4 = 12",50    "nums[q] * nums[s] = nums[2] * nums[7] = 3 * 4 = 12",51    "7 <= nums.length <= 1000",52    "1 <= nums[i] <= 1000"53  ],54  "python_template": "class Solution(object):\n    def numberOfSubsequences(self, nums):\n        \"\"\"\n        :type nums: List[int]\n        :rtype: int\n        \"\"\"\n        ",55  "java_template": "class Solution {\n    public long numberOfSubsequences(int[] nums) {\n        \n    }\n}",56  "metadata": {57    "func_name": "numberOfSubsequences"58  }59}