Article directory
1. Title
Pair exchange. Write a program that swaps the odd and even bits of an integer using as few instructions as possible (that is, swap bit 0 with bit 1, bit 2 with bit 3, and so on).
Example 1:
Input: num = 2 (or 0b10)
Output : 1 (or 0b01)
Example 2:
Input: num = 3
Output: 3
hint:
numThe range is[0, 2^30 - 1]between and no integer overflow will occur.
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2. Java problem solving
It's relatively simple, just put the code directly.
class Solution {
public int exchangeBits(int num) {
int ans = 0, even, odd;
for (int i = 0; i < 32; i += 2) {
even = 1 << i;
odd = 1 << (i + 1);
if ((num & even) != 0) ans |= odd;
if ((num & odd) != 0) ans |= even;
}
return ans;
}
}
- Time: 0 ms, beats 100.00% of users using Java
- Memory: 36.79 MB, beats 96.88% of users using Java