package me.ramswaroop.bits;
/**
* Created by IntelliJ IDEA.
*
* @author: ramswaroop
* @date: 7/22/15
* @time: 12:42 PM
*/
public class CountSetBitsFromMinusNtoN {
/**
* Explanation:
*
* -3: 101
* -2: 110
* -1: 111
* 0: 000
* 1: 001
* 2: 010
* 3: 110
*
* If you fold the above representation between -1 and 0, the total no. of set bits from -3 to 2
* will be equal to the total no. of bits in nos. from -3 to 2.
*
* @param n
* @return
*/
public static int countSetBitsFromMinusNtoN(int n) {
return n * 32 + CountSetBits.countSetBits((long) n); // 32 because int is of 32 bits in java
}
public static void main(String a[]) {
System.out.println(countSetBitsFromMinusNtoN(3));
System.out.println(countSetBitsFromMinusNtoN(0));
System.out.println(countSetBitsFromMinusNtoN(9));
}
}