Bit Manipulation, Easy
Question
Given a positive integer, check whether it has alternating bits: namely, if two adjacent bits will always have different values.
Example 1:
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Input: 5 Output: True Explanation: The binary representation of 5 is: 101
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Example 2:
1 2 3 4
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Input: 7 Output: False Explanation: The binary representation of 7 is: 111.
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Example 3:
1 2 3 4
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Input: 11 Output: False Explanation: The binary representation of 11 is: 1011.
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Example 4:
1 2 3 4
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Input: 10 Output: True Explanation: The binary representation of 10 is: 1010.
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My Answer
1 2 3 4 5
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class { public boolean hasAlternatingBits(int n) { return (((long)n + (n>>1) + 1) & ((long)n + (n>>1))) == 0; } }
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Running time: O(n), n is the length bit of the given number， 15ms
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