chlng

Author: YuriSpiridonov

Challenges/2021/January-LeetCoding-Challenge.md

@@ -41,7 +41,7 @@ None
 |1679.|[Max Number of K-Sum Pairs](https://leetcode.com/problems/max-number-of-k-sum-pairs/)|[Python](/Medium/1679.MaxNumberofK-SumPairs.py)|Medium|
 |5.|[Longest Palindromic Substring](https://leetcode.com/problems/longest-palindromic-substring/)|[Python](Medium/5.LongestPalindromicSubstring(bruteforce).py)|Medium|
 |20.|[Valid Parentheses](https://leetcode.com/problems/valid-parentheses/)|[Python](/Easy/20.ValidParentheses(Stack).py)|Easy|
-
+|1673.|[Find the Most Competitive Subsequence](https://leetcode.com/problems/find-the-most-competitive-subsequence/)|[Python](/Medium/1673.FindtheMostCompetitiveSubsequence.py)|Medium|
 
 ## License
 The code is open-source and licensed under the [MIT License](/LICENSE).

Challenges/README.md

@@ -7,4 +7,4 @@
 - [December LeetCoding Challenge](/Challenges/2020/December-LeetCoding-Challenge.md) - 27/31
 
 2021:
-- [January LeetCoding Challenge](/Challenges/2021/January-LeetCoding-Challenge.md) - 18/31
+- [January LeetCoding Challenge](/Challenges/2021/January-LeetCoding-Challenge.md) - 19/31

Medium/1673.FindtheMostCompetitiveSubsequence.py

@@ -0,0 +1,50 @@
+"""
+    Given an integer array nums and a positive integer k, 
+    return the most competitive subsequence of nums of size 
+    k.
+
+    An array's subsequence is a resulting sequence obtained 
+    by erasing some (possibly zero) elements from the array.
+
+    We define that a subsequence a is more competitive than 
+    a subsequence b (of the same length) if in the first 
+    position where a and b differ, subsequence a has a 
+    number less than the corresponding number in b. For 
+    example, [1,3,4] is more competitive than [1,3,5] 
+    because the first position they differ is at the final 
+    number, and 4 is less than 5.
+
+    Example:
+    Input: nums = [3,5,2,6], k = 2
+    Output: [2,6]
+    Explanation: Among the set of every possible subsequence: 
+                 {[3,5], [3,2], [3,6], [5,2], [5,6], [2,6]}, 
+                 [2,6] is the most competitive.
+
+    Example:
+    Input: nums = [2,4,3,3,5,4,9,6], k = 4
+    Output: [2,3,3,4]
+
+    Constraints:
+        - 1 <= nums.length <= 10^5
+        - 0 <= nums[i] <= 10^9
+        - 1 <= k <= nums.length
+"""
+#Difficulty: Medium
+#86 / 86 test cases passed.
+#Runtime: 1256 ms
+#Memory Usage: 27.1 MB
+
+#Runtime: 1256 ms, faster than 78.12% of Python3 online submissions for Find the Most Competitive Subsequence.
+#Memory Usage: 27.1 MB, less than 81.07% of Python3 online submissions for Find the Most Competitive Subsequence.
+
+class Solution:
+    def mostCompetitive(self, nums: List[int], k: int) -> List[int]:
+        length = len(nums) - k
+        stack = []
+        for num in nums:
+            while stack and stack[-1] > num and length:
+                stack.pop()
+                length -= 1
+            stack.append(num)
+        return stack[:k]

Medium/402.RemoveKDigits.py

@@ -0,0 +1,50 @@
+'''
+    Given a non-negative integer num represented as a string, 
+    remove k digits from the number so that the new number 
+    is the smallest possible.
+
+    Note:
+        - The length of num is less than 10002 and will 
+          be ≥ k.
+        - The given num does not contain any leading zero.
+
+    Example:
+    Input: num = "1432219", k = 3
+    Output: "1219"
+    Explanation: Remove the three digits 4, 3, and 2 to 
+                 form the new number 1219 which is the 
+                 smallest.
+
+    Example:
+    Input: num = "10200", k = 1
+    Output: "200"
+    Explanation: Remove the leading 1 and the number is 200. 
+                 Note that the output must not contain 
+                 leading zeroes.
+
+    Example:
+    Input: num = "10", k = 2
+    Output: "0"
+    Explanation: Remove all the digits from the number and 
+                 it is left with nothing which is 0.
+'''
+#Difficlty: Medium
+#33 / 33 test cases passed.
+#Runtime: 32 ms
+#Memory Usage: 14.1 MB
+
+#Runtime: 32 ms, faster than 92.66% of Python3 online submissions for Remove K Digits.
+#Memory Usage: 14.1 MB, less than 99.94% of Python3 online submissions for Remove K Digits.
+
+class Solution:
+    def removeKdigits(self, num: str, k: int) -> str:
+        length = len(num) - k
+        stack = []
+        for n in num:
+            while stack and k and stack[-1] > n:
+                stack.pop()
+                k -= 1
+            stack.append(n)
+        while stack and stack[0] == '0':
+            stack.pop(0)
+        return ''.join(stack)[:length] if stack and length else '0'

README.md

@@ -1,6 +1,6 @@
 # Python solutions of LeetCode problems.
 ![Language](https://img.shields.io/badge/language-Python-blue.svg) 
-![Problems Solved](https://img.shields.io/badge/problems%20solved-496%2F1571-orange) 
+![Problems Solved](https://img.shields.io/badge/problems%20solved-499%2F1571-orange) 
 [![License](https://img.shields.io/badge/license-MIT-green.svg)](./LICENSE) 
 ![Update](https://img.shields.io/badge/update-Daily-brightgreen.svg) 
 <br><br>
@@ -19,7 +19,7 @@ In this repository provided my Python solutions of LeetCode problems.
 - [December LeetCoding Challenge](/Challenges/2020/December-LeetCoding-Challenge.md) - 27/31
 
 2021:
-- [January LeetCoding Challenge](/Challenges/2021/January-LeetCoding-Challenge.md) - 18/31
+- [January LeetCoding Challenge](/Challenges/2021/January-LeetCoding-Challenge.md) - 19/31
 <br><br>
 ## Solutions
 *P.S. If you like this, please leave me a star.* ★
@@ -209,6 +209,7 @@ In this repository provided my Python solutions of LeetCode problems.
 |395.|[Longest Substring with At Least K Repeating Characters](https://leetcode.com/problems/longest-substring-with-at-least-k-repeating-characters/)|[Python](/Medium/395.LongestSubstringwithAtLeastKRepeatingCharacters.py)|Medium|`collections`, `Recursion`|
 |398.|[Random Pick Index](https://leetcode.com/problems/random-pick-index/)|[Python](/Medium/398.RandomPickIndex.py)|Medium|`random.choice()`|
 |399.|[Evaluate Division](https://leetcode.com/problems/evaluate-division/)|[Python](/Medium/399.EvaluateDivision.py)|Medium|God bless youtube|
+|402.|[Remove K Digits](https://leetcode.com/problems/remove-k-digits/)|[Python](/Medium/402.RemoveKDigits.py)|Medium|`Stack`|
 |404.|[Sum of Left Leaves](https://leetcode.com/problems/sum-of-left-leaves/)|[Python](/Easy/404.SumofLeftLeaves.py)|Easy|`Recursion`, preorder|
 |409.|[Longest Palindrome](https://leetcode.com/problems/longest-palindrome/)|[Python](/Easy/409.LongestPalindrome.py)|Easy||
 |412.|[Fizz Buzz](https://leetcode.com/problems/fizz-buzz/)|[Python](/Easy/412.FizzBuzz.py)|Easy||
@@ -524,6 +525,7 @@ In this repository provided my Python solutions of LeetCode problems.
 |1669.|[Merge In Between Linked Lists](https://leetcode.com/problems/merge-in-between-linked-lists/)|[Python](/Medium/1669.MergeInBetweenLinkedLists.py)|Medium|`Linked List`|
 |1670.|[Design Front Middle Back Queue](https://leetcode.com/problems/design-front-middle-back-queue/)|[Python](/Medium/1670.DesignFrontMiddleBackQueue.py)|Medium|`List`|
 |1672.|[Richest Customer Wealth](https://leetcode.com/problems/richest-customer-wealth/)|[Python](/Easy/1672.RichestCustomerWealth.py)|Easy||
+|1673.|[Find the Most Competitive Subsequence](https://leetcode.com/problems/find-the-most-competitive-subsequence/)|[Python](/Medium/1673.FindtheMostCompetitiveSubsequence.py)|Medium|`Stack`|
 |1678.|[Goal Parser Interpretation](https://leetcode.com/problems/goal-parser-interpretation/)|[Python](/Easy/1678.GoalParserInterpretation(replace).py)|Easy|`.replace()`|
 |1678.|[Goal Parser Interpretation](https://leetcode.com/problems/goal-parser-interpretation/)|[Python](/Easy/1678.GoalParserInterpretation.py)|Easy|iteratively|
 |1679.|[Max Number of K-Sum Pairs](https://leetcode.com/problems/max-number-of-k-sum-pairs/)|[Python](/Medium/1679.MaxNumberofK-SumPairs.py)|Medium|`collections`, `Counter`|