Given a binary number as a string str of length L. The task is to find the minimum number of operations needed so that the number becomes 2L-1, that is a string consisting of only 1’s of the length L.
In each operation, the number N can be replaced by N xor (N + 1).
Input: str = “10010111”
N = 10010111, N + 1 = 10011000, so N xor (N + 1) = 00001111
N = 00001111, N + 1 = 00010000, so N xor (N + 1) = 00011111
N = 00011111, N + 1 = 00100000, so N xor (N + 1) = 00111111
N = 00111111, N + 1 = 01000000, so N xor (N + 1) = 01111111
N = 01111111, N + 1 = 10000000, so N xor (N + 1) = 11111111
Input: str = “101000100101011101”
Approach: After performing the given operation, it can be observed that in order to get the required number, in the end, the number of operations will be:
Number of Operations = length of the string (after removing leading 0s) – count of consecutive 1’s form the end (starting from the least significant bit)
Below is the implementation of the above approach:
Time Complexity: O(n)
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