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+# 1375. Number of Times Binary String Is Prefix-Aligned
+
+"""
+you have a 1 indexed binary string of length 'n' where all the bits are 0
+initially. we will flip all the bits of this binary string one by one. you
+are given a 1 indexed integer array 'flips' where 'flips[i]' indicates that
+the bit at index 'i' will be flipped in the i'th step. a binar y string is
+prefix aligned if after the i'th step, all the bits in the inclusive range
+'[1, i]' are ones and all the other bits are zeros. return the number of
+times the binary string is prefix aligned during the flipping process.
+"""
+
+
+class Solution(object):
+ def numTimesAllBlue(self, flips):
+ """
+ :type flips: List[int]
+ :rtype: int
+ """
+ ans, state = 0, 0
+ for i in flips:
+ state = state | (1 << (i - 1))
+ if state & (state + 1) == 0:
+ ans += 1
+ return ans
+
+
+if __name__ == "__main__":
+ obj = Solution()
+ print(obj.numTimesAllBlue([3, 2, 4, 1, 5]))
+ print(obj.numTimesAllBlue([4, 1, 2, 3]))