Question5_1.java

/**
 * You are given two 32-bit numbers, N and M, and two bit positions, i and j.
 * Write a method to insert M into N such that M starts at bit j and ends at bit i.
 * You can assume that the bits j through i have enough space to fit all of M.
 * That is, if M = 10011, you can assume that there are at least 5 bits between j and i.
 * You would not, for example, have j = 3 and i = 2, because M could not fully fit between bit 3 and bit 2.
 * 
 * EXAMPLE
 * Input:  N = 10000000000, M = 10011, i = 2, j = 6
 * Output: N = 10001001100
 * 
 * Time  Complexity: O(1)
 * Space Complexity: O(1)
 */

public class Question5_1 {
    public int insert(int m, int n, int i, int j) {
        return (m << i) | (((1 << i) - 1) | ~(-1 >>> (31 - j))) & n;
    }
    
    public static void main(String[] args) {
        Question5_1 question5_1 = new Question5_1();
        System.out.println(Integer.toBinaryString((question5_1.insert(0b10011, 0b10000000000, 2, 6))));
    }
}