Given a string s, return the length of the longest palindromic subsequence in s. A subsequence is a sequence derived by deleting some or no elements without changing the order of the remaining elements.
You are given a binary grid of size m x n, where each cell is initially set to 0. The task is to design an algorithm that can randomly pick a cell that is still 0, flip it to 1, and ensure that all available cells are equally likely to be selected.
Given an array of strings strs, determine the length of the longest uncommon subsequence between them. An uncommon subsequence is a string that is a subsequence of one string but not the others. If no such subsequence exists, return -1.
