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[LeetCode] Ways to Express an Integer as Sum of Powers 2023-07-22|PSLeetCode|Problem Solving-Dynamic Programming-Combinatorics

2787. Ways to Express an Integer as Sum of Powers

Given two positive integers n and x.

Return the number of ways n can be expressed as the sum of the xth power of unique positive integers, in other words, the number of sets of unique integers [n1, n2, ..., nk] where n = n1x + n2x + ... + nkx.

Since the result can be very large, return it modulo 109 + 7.

For example, if n = 160 and x = 3, one way to express n is n = 23 + 33 + 53.

[LeetCode] Visit Array Positions to Maximize Score 2023-07-22|PSLeetCode|Problem Solving-Dynamic Programming

2786. Visit Array Positions to Maximize Score

You are given a 0-indexed integer array nums and a positive integer x.

You are initially at position 0 in the array and you can visit other positions according to the following rules:

If you are currently in position i, then you can move to any position j such that i < j.

For each position i that you visit, you get a score of nums[i].

If you move from a position i to a position j and the parities of nums[i] and nums[j] differ, then you lose a score of x.

Return the maximum total score you can get.

Note that initially you have nums[0] points.

[LeetCode] Sort Vowels in a String 2023-07-22|PSLeetCode|Problem Solving

2785. Sort Vowels in a String

Given a 0-indexed string s, permute s to get a new string t such that:

All consonants remain in their original places. More formally, if there is an index i with 0 <= i < s.length such that s[i] is a consonant, then t[i] = s[i].

The vowels must be sorted in the nondecreasing order of their ASCII values. More formally, for pairs of indices i, j with 0 <= i < j < s.length such that s[i] and s[j] are vowels, then t[i] must not have a higher ASCII value than t[j].

Return the resulting string.

The vowels are 'a', 'e', 'i', 'o', and 'u', and they can appear in lowercase or uppercase. Consonants comprise all letters that are not vowels.

[LeetCode] Check if Array is Good 2023-07-22|PSLeetCode|Problem Solving

2784. Check if Array is Good

You are given an integer array nums. We consider an array good if it is a permutation of an array base[n].

base[n] = [1, 2, ..., n - 1, n, n](in other words, it is an array of length n + 1 which contains 1 to n - 1exactly once, plus two occurrences of n). For example, base[1] = [1, 1] andbase[3] = [1, 2, 3, 3].

Return true if the given array is good, otherwise return false.

Note: A permutation of integers represents an arrangement of these numbers.