QUESTION:
Every non-negative integer N has a binary representation. For example, 5 can be represented as "101" in binary, 11 as "1011" in binary, and so on. Note that except for N = 0, there are no leading zeroes in any binary representation.
The complement of a binary representation is the number in binary you get when changing every 1 to a 0 and 0 to a 1. For example, the complement of "101" in binary is "010" in binary.
For a given number N in base-10, return the complement of it’s binary representation as a base-10 integer.
Example 1:
Input: 5
Output: 2
Explanation: 5 is "101" in binary, with complement "010" in binary, which is 2 in base-10.
Example 2:
Input: 7
Output: 0
Explanation: 7 is "111" in binary, with complement "000" in binary, which is 0 in base-10.
Example 3:
Input: 10
Output: 5
Explanation: 10 is "1010" in binary, with complement "0101" in binary, which is 5 in base-10.
Note:
0 <= N < 10^9
EXPLANATION:
这个比较简单，直接看代码就可以了。
SOLUTION:
class Solution {
public int bitwiseComplement(int N) {
boolean found = false;
String result = "";
String bin = Integer.toBinaryString(N);
for (char c:bin.toCharArray()){
if(c=='1') result = result+0;
else result = result+1;
}
return Integer.parseInt(result,2);
}
}