3094-GuessTheNumberUsingBitwiseQuestionsII.go

package main

// 3094. Guess the Number Using Bitwise Questions II
// There is a number n between 0 and 2^30 - 1 (both inclusive) that you have to find.

// There is a pre-defined API int commonBits(int num) that helps you with your mission. 
// But here is the challenge, every time you call this function, n changes in some way. 
// But keep in mind, that you have to find the initial value of n.

// commonBits(int num) acts as follows:
//     Calculate count which is the number of bits where both n and num have the same value in that position of their binary representation.
//     n = n XOR num
//     Return count.

// Return the number n.

// Note: In this world, all numbers are between 0 and 2^30 - 1 (both inclusive), 
// thus for counting common bits, we see only the first 30 bits of those numbers.

// Constraints:
//     0 <= n <= 2^30 - 1
//     0 <= num <= 2^30 - 1
//     If you ask for some num out of the given range, the output wouldn't be reliable.

import "fmt"

/** 
 * Definition of commonBits API.
 * func commonBits(num int) int;
 */
func findNumber() int {
    res, zeroBits := 0, commonBits(0)
    for i := 0; i < 30; i++ {
        if commonBits(1 << i) > zeroBits {
            res += 1 << i
        }
        commonBits(1 << i)
    }
    return res
}

func main() {
    fmt.Println()
}