[LeetCode] Maximum Number of Vowels in a Substring of Given Length

1456. Maximum Number of Vowels in a Substring of Given Length

Given a string s and an integer k, return the maximum number of vowel letters in any substring of s with length k.

Vowel letters in English are ‘a’, ‘e’, ‘i’, ‘o’, and ‘u’.

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[LeetCode] Adding Spaces to a String

2109. Adding Spaces to a String

You are given a 0-indexed string s and a 0-indexed integer array spaces that describes the indices in the original string where spaces will be added. Each space should be inserted before the character at the given index.

  • For example, given s = “EnjoyYourCoffee” and spaces = [5, 9], we place spaces before ‘Y’ and ‘C’, which are at indices 5 and 9 respectively. Thus, we obtain “Enjoy Your Coffee”.

Return the modified string after the spaces have been added.

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[LeetCode] Form Array by Concatenating Subarrays of Another Array

1764. Form Array by Concatenating Subarrays of Another Array

You are given a 2D integer array groups of length n. You are also given an integer array nums.

You are asked if you can choose n disjoint subarrays from the array nums such that the ith subarray is equal to groups[i] (0-indexed), and if i > 0, the (i-1)th subarray appears before the ith subarray in nums (i.e. the subarrays must be in the same order as groups).

Return true if you can do this task, and false otherwise.

Note that the subarrays are disjoint if and only if there is no index k such that nums[k] belongs to more than one subarray. A subarray is a contiguous sequence of elements within an array.

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[LeetCode] Minimum Garden Perimeter to Collect Enough Apples

1954. Minimum Garden Perimeter to Collect Enough Apples

In a garden represented as an infinite 2D grid, there is an apple tree planted at every integer coordinate. The apple tree planted at an integer coordinate (i, j) has |i| + |j| apples growing on it.

You will buy an axis-aligned square plot of land that is centered at (0, 0).

Given an integer neededApples, return the minimum perimeter of a plot such that at least neededApples apples are inside or on the perimeter of that plot.

The value of |x| is defined as:

  • x if x >= 0
  • -x if x < 0
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[LeetCode] Number of Steps to Reduce a Number in Binary Representation to One

1404. Number of Steps to Reduce a Number in Binary Representation to One

Given the binary representation of an integer as a string s, return the number of steps to reduce it to 1 under the following rules:

  • If the current number is even, you have to divide it by 2.
  • If the current number is odd, you have to add 1 to it.

It is guaranteed that you can always reach one for all test cases.

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[AtCoder] C - Happy New Year!Read more
[AtCoder] E - Arithmetic NumberRead more
[AtCoder] D - Prefix K-th MaxRead more
[AtCoder] E - SkiingRead more
[AtCoder] D - LR insertionRead more