1. What are the benefits for merchants using QR codes?
2. Given an array of integers heights representing the histogram's bar height where the width of each bar is 1, return the area of the largest rectangle in the histogram.
3. How to sale a product. Plz sale this item .
4. What do you know about the credit industry?
5. Given an array, find the next greater element (NGE) for every element. The Next greater Element for an element x is the first greater element on the right side of x in the array. Elements for which no greater element exist, consider the next greater element as -1.