File size: 2,880 Bytes
6cf60f3 | 1 2 3 4 5 6 7 8 9 10 11 12 | [
{
"question": "You are given a 0-indexed array of positive integers nums. Find the number of triplets (i, j, k) that meet the following conditions:\n\n0 <= i < j < k < nums.length\nnums[i], nums[j], and nums[k] are pairwise distinct.\n\t\nIn other words, nums[i] != nums[j], nums[i] != nums[k], and nums[j] != nums[k].\n\n\n\nReturn the number of triplets that meet the conditions.\n \nExample 1:\n\nInput: nums = [4,4,2,4,3]\nOutput: 3\nExplanation: The following triplets meet the conditions:\n- (0, 2, 4) because 4 != 2 != 3\n- (1, 2, 4) because 4 != 2 != 3\n- (2, 3, 4) because 2 != 4 != 3\nSince there are 3 triplets, we return 3.\nNote that (2, 0, 4) is not a valid triplet because 2 > 0.\n\nExample 2:\n\nInput: nums = [1,1,1,1,1]\nOutput: 0\nExplanation: No triplets meet the conditions so we return 0.\n\n \nConstraints:\n\n3 <= nums.length <= 100\n1 <= nums[i] <= 1000\n\n",
"sample_code": "class Solution:\n def unequalTriplets(self, nums: List[int]) -> int:\n ",
"answer": "class Solution:\n def unequalTriplets(self, a: List[int]) -> int:\n ans = 0\n n = len(a)\n for i in range(n):\n for j in range(i + 1, n):\n for k in range(j + 1, n):\n ans += len({a[i], a[j], a[k]}) == 3\n return ans"
},
{
"question": "You are given two strings s and t consisting of only lowercase English letters.\nReturn the minimum number of characters that need to be appended to the end of s so that t becomes a subsequence of s.\nA subsequence is a string that can be derived from another string by deleting some or no characters without changing the order of the remaining characters.\n \nExample 1:\n\nInput: s = \"coaching\", t = \"coding\"\nOutput: 4\nExplanation: Append the characters \"ding\" to the end of s so that s = \"coachingding\".\nNow, t is a subsequence of s (\"coachingding\").\nIt can be shown that appending any 3 characters to the end of s will never make t a subsequence.\n\nExample 2:\n\nInput: s = \"abcde\", t = \"a\"\nOutput: 0\nExplanation: t is already a subsequence of s (\"abcde\").\n\nExample 3:\n\nInput: s = \"z\", t = \"abcde\"\nOutput: 5\nExplanation: Append the characters \"abcde\" to the end of s so that s = \"zabcde\".\nNow, t is a subsequence of s (\"zabcde\").\nIt can be shown that appending any 4 characters to the end of s will never make t a subsequence.\n\n \nConstraints:\n\n1 <= s.length, t.length <= 10^5\ns and t consist only of lowercase English letters.\n\n",
"sample_code": "class Solution:\n def appendCharacters(self, s: str, t: str) -> int:\n ",
"answer": "class Solution:\n def appendCharacters(self, s: str, t: str) -> int:\n i = 0\n for char in s:\n if i < len(t) and char == t[i]:\n i += 1\n return len(t) - i"
}
] |