Flipkart SDE-intern interview questions

2 questions were asked. There are n houses in society, with each containing some value in it. A thief should steal the maximum he can. He can’t steal from any two adjacent houses since society has an alarming system. Find the maximum value he can steal. (First done using DP but the interviewer asked to reduce space complexity). There is an enumerated complete binary tree (i.e., elements are 1,2,3…). Given an element (key) find whether it is present or not in the tree. (First done with traversing the tree and searching which is O(n) and the interviewer asked to reduce the time complexity)