Codeforces Round 460 (Div. 2) E. Congruence Equation

3077. Maximum Strength of K Disjoint Subarrays

You are given a 0-indexed array of integers nums of length n, and a positive odd integer k.

The strength of x subarrays is defined as strength = sum[1] * x - sum[2] * (x - 1) + sum[3] * (x - 2) - sum[4] * (x - 3) + ... + sum[x] * 1 where sum[i] is the sum of the elements in the ith subarray. Formally, strength is sum of (-1)i+1 * sum[i] * (x - i + 1) over all i‘s such that 1 <= i <= x.

You need to select k disjoint subarrays from nums, such that their strength is maximum.

Return the maximum possible strength that can be obtained.

Note that the selected subarrays don’t need to cover the entire array.

3076. Shortest Uncommon Substring in an Array

You are given an array arr of size n consisting of non-empty strings.

Find a string array answer of size n such that:

• answer[i] is the shortest substring of arr[i] that does not occur as a substring in any other string in arr. If multiple such substrings exist, answer[i] should be the lexicographically smallest. And if no such substring exists, answer[i] should be an empty string.

Return the array answer.

3075. Maximize Happiness of Selected Children

You are given an array happiness of length n, and a positive integer k.

There are n children standing in a queue, where the ith child has happiness value happiness[i]. You want to select k children from these n children in k turns.

In each turn, when you select a child, the happiness value of all the children that have not been selected till now decreases by 1. Note that the happiness value cannot become negative and gets decremented only if it is positive.

Return the maximum sum of the happiness values of the selected children you can achieve by selecting k children.

3074. Apple Redistribution into Boxes

You are given an array apple of size n and an array capacity of size m.

There are n packs where the ith pack contains apple[i] apples. There are m boxes as well, and the ith box has a capacity of capacity[i] apples.

Return the minimum number of boxes you need to select to redistribute these n packs of apples into boxes.

Note that, apples from the same pack can be distributed into different boxes.

3064. Guess the Number Using Bitwise Questions I

There is a number n that you have to find.

There is also a pre-defined API int commonSetBits(int num), which returns the number of bits where both n and num are 1 in that position of their binary representation. In other words, it returns the number of set bits in n & num, where & is the bitwise AND operator.

Return the number n.

349. Intersection of Two Arrays

Given two integer arrays nums1 and nums2, return an array of their intersection. Each element in the result must be unique and you may return the result in any order.

Longest Increasing Path

Rotate, rotate again and rotate once more

Ma5termind and XOR Minimization