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Copy file name to clipboardExpand all lines: solution/3300-3399/3314.Construct the Minimum Bitwise Array I/README_EN.md
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### Solution 1
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### Solution 1: Bit Manipulation
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For an integer $a$, the result of $a \lor (a + 1)$ is always odd. Therefore, if $\text{nums[i]}$ is even, then $\text{ans}[i]$ does not exist, and we directly return $-1$. In this problem, $\textit{nums}[i]$ is a prime number, so to check if it is even, we only need to check if it equals $2$.
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If $\text{nums[i]}$ is odd, suppose $\text{nums[i]} = \text{0b1101101}$. Since $a \lor (a + 1) = \text{nums[i]}$, this is equivalent to changing the last $0$ bit of $a$ to $1$. To solve for $a$, we need to change the bit after the last $0$ in $\text{nums[i]}$ to $0$. We start traversing from the least significant bit (index $1$) and find the first $0$ bit. If it is at position $i$, we change the $(i - 1)$-th bit of $\text{nums[i]}$ to $1$, i.e., $\text{ans}[i] = \text{nums[i]} \oplus 2^{i - 1}$.
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By traversing all elements in $\text{nums}$, we can obtain the answer.
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The time complexity is $O(n \times \log M)$, where $n$ and $M$ are the length of the array $\text{nums}$ and the maximum value in the array, respectively. Ignoring the space consumption of the answer array, the space complexity is $O(1)$.
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