Codeforces Round #774 (Div. 2) C. Factorials and Powers of Two
1989. Maximum Number of People That Can Be Caught in Tag
You are playing a game of tag with your friends. In tag, people are divided into two teams: people who are “it”, and people who are not “it”. The people who are “it” want to catch as many people as possible who are not “it”.
You are given a 0-indexed integer array team containing only zeros (denoting people who are not “it”) and ones (denoting people who are “it”), and an integer dist. A person who is “it” at index i can catch any one person whose index is in the range [i - dist, i + dist]
(inclusive)and is not “it”.Return the maximum number of people that the people who are “it” can catch.
1992. Find All Groups of Farmland
You are given a 0-indexed m x n binary matrix land where a 0 represents a hectare of forested land and a 1 represents a hectare of farmland.
To keep the land organized, there are designated rectangular areas of hectares that consist entirely of farmland. These rectangular areas are called groups. No two groups are adjacent, meaning farmland in one group is not four-directionally adjacent to another farmland in a different group.
land can be represented by a coordinate system where the top left corner of land is (0, 0) and the bottom right corner of land is (m-1, n-1). Find the coordinates of the top left and bottom right corner of each group of farmland. A group of farmland with a top left corner at (r1, c1) and a bottom right corner at (r2, c2) is represented by the 4-length array [r1, c1, r2, c2].
Return a 2D array containing the 4-length arrays described above for each group of farmland in land. If there are no groups of farmland, return an empty array. You may return the answer in any order.
1999. Smallest Greater Multiple Made of Two Digits
Given three integers, k, digit1, and digit2, you want to find the smallest integer that is:
- Larger than k,
- A multiple of k, and
- Comprised of only the digits digit1 and/or digit2.
Return the smallest such integer. If no such integer exists or the integer exceeds the limit of a signed 32-bit integer (231 - 1), return -1.
2001. Number of Pairs of Interchangeable Rectangles
You are given n rectangles represented by a 0-indexed 2D integer array rectangles, where rectangles[i] = [widthi, heighti] denotes the width and height of the ith rectangle.
Two rectangles i and j (i < j) are considered interchangeable if they have the same width-to-height ratio. More formally, two rectangles are interchangeable if widthi/heighti == widthj/heightj (using decimal division, not integer division).
Return the number of pairs of interchangeable rectangles in rectangles.
2002. Maximum Product of the Length of Two Palindromic Subsequences
Given a string s, find two disjoint palindromic subsequences of s such that the product of their lengths is maximized. The two subsequences are disjoint if they do not both pick a character at the same index.
Return the maximum possible product of the lengths of the two palindromic subsequences.
A 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. A string is palindromic if it reads the same forward and backward.