Given a number X, the task is to find the minimum number N such that total set bits of all numbers from 1 to n is atleast X.
Input: x = 5 Output: 4 Set bits in 1-> 1 Set bits in 2-> 1 Set bits in 3-> 2 Set bits in 4-> 1 Hence first four numbers add upto 5 Input: x = 20 Output: 11
Approach: Use binary search to get the minimum most number whose sum of bits till N is atleast X. At start, low is 0 and high is initialized according to the constraint. Check if count of set bits is atleast X, every time it is, change high to mid-1, else change it to mid+1. Everytime we do high = mid-1, store the minimal of answer.
Below is the implementation of the above approach:
Time Complexity: O(log N * log N)
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