Hi, I recently appeared for Amazon OA which consisted 2 questions, one was quite easy and straighforward on Pascal\'s encryption of a string. Second was a bit tricky and based on the constraints I needed to code O(nlogn) if not O(n) solution. \n\n**Min-Max Product**\n\nYou are given an array, you need to find sum of powers of all contigous sub-array, where power[i, j] is the power of sub-array starting from ith position till jth position and is defined as below :\n\n![image](https://assets.leetcode.com/users/images/3806d672-75ef-43ce-8aa2-2cdf48185f24_1643089142.6617615.png)\n\n\n\nFor example :\n\narray = [2, 4, 3, 1, 2, 4, 8]\n\n```\npower[0, 3] = min(0...3) x summation(0...3)\n\npower[0, 3] = min (2, 4, 3, 1) x (2 + 4 + 3 + 1)\n\npower[0, 3] = 1 x 10 = 10\n```\n\nWe will do this for all the contiguous sub-arrays and at the end print the sum of all such powers. \n\n```\nfinal_ans = power[0, 0] + power[0, 1] + power[0, 2] + ... + power[1, 1] + power[1, 2] + power[1, 3] + ... + power[2, 2] + power[2, 3] + ...\n\nfinal_ans = final_ans % 1000000007\n```\n\nIt was a bit hard for me tbh, couldn\'t think of anything above the obvious brute-force. Would love to know the approaches here. Thanks!

Hi, I recently appeared for Amazon OA which consisted 2 questions, one was quite easy and straighforward on Pascal\'s encryption of a string. Second was a bit t