Question

How to round a number to the nearest power of 2 in Java

Answer 1

public class NearestPowerOfTwo {

    /**
     * Rounds a positive integer to the nearest power of 2.
     *
     * return the nearest power of 2
     */
    public static int roundToNearestPowerOf2(int n) {
        if (n <= 0) return 0;

        int prevPower = Integer.highestOneBit(n);
        int nextPower = prevPower << 1;

        return (n - prevPower < nextPower - n) ? prevPower : nextPower;
    }

    public static void main(String[] args) {
        int num = 37;
        
        System.out.println("Nearest power of 2: " + roundToNearestPowerOf2(num));
    }
}



/*
run:

Nearest power of 2: 32

*/

 

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