LeetCode-in-Java
1009. Complement of Base 10 Integer
Easy
The complement of an integer is the integer you get when you flip all the 0’s to 1’s and all the 1’s to 0’s in its binary representation.
- For example, The integer
5is"101"in binary and its complement is"010"which is the integer2.
Given an integer n, return its complement.
Example 1:
Input: n = 5
Output: 2
Explanation: 5 is “101” in binary, with complement “010” in binary, which is 2 in base-10.
Example 2:
Input: n = 7
Output: 0
Explanation: 7 is “111” in binary, with complement “000” in binary, which is 0 in base-10.
Example 3:
Input: n = 10
Output: 5
Explanation: 10 is “1010” in binary, with complement “0101” in binary, which is 5 in base-10.
Constraints:
0 <= n < 109
Note: This question is the same as 476: https://leetcode.com/problems/number-complement/
Solution
import java.util.ArrayList;
import java.util.List;
public class Solution {
public int bitwiseComplement(int n) {
if (n == 0) {
return 1;
}
List<Integer> list = new ArrayList<>();
while (n != 0) {
list.add(n & 1);
n >>= 1;
}
int result = 0;
int exp = list.size() - 1;
for (int i = list.size() - 1; i >= 0; i--) {
if (list.get(i) == 0) {
result += Math.pow(2, exp);
}
exp--;
}
return result;
}
}