Design a system that processes daily stock price quotes and computes the price span for the current day. The price span for a day is defined as the maximum number of consecutive days (including today) where the price of the stock was less than or equal to today’s price.
Given an array of integers arr, find the sum of the minimum values of all contiguous subarrays of arr. Since the result can be very large, return it modulo 10^9 + 7.
You are given a string consisting of parentheses. In one move, you can insert a parenthesis (either ‘(’ or ‘)’) at any position in the string. Your task is to return the minimum number of moves required to make the string valid, meaning all parentheses are properly balanced.
You are given two integer arrays, pushed and popped, each containing distinct values. The arrays represent the order of elements being pushed onto and popped from an initially empty stack. Your task is to determine if it is possible to obtain the popped sequence from the pushed sequence through a series of valid stack push and pop operations.
You are given an integer array nums. A ramp in the array is a pair of indices (i, j) where i < j and nums[i] <= nums[j]. The width of the ramp is calculated as the difference between j and i (i.e., j - i). Your task is to find the maximum width of a ramp in the given array. If no such ramp exists, return 0.
You are given a string s consisting of only the characters ‘a’, ‘b’, and ‘c’. A string is considered valid if it can be formed by repeatedly inserting the substring ‘abc’ into any position of an empty string. Your task is to determine if s can be a valid string after performing this operation any number of times.