2021.01.25 연습

 

  • 사용언어 : java

 

class Solution {
    public int numberOfSteps (int num) {
        
        int count = 0;
        
        while (num>0) {
            
            if (num%2 == 0) {
                num = num/2;
            } else {
                num--;
            }
            count++;
            
        }
        
        return count;
    }
}

Runtime: 0 ms, faster than 100.00% of Java online submissions for Number of Steps to Reduce a Number to Zero. Memory Usage: 35.6 MB, less than 78.90% of Java online submissions for Number of Steps to Reduce a Number to Zero.

  • 다른 코드 참고
//Method 1: Iterative
//T: O(n), S: O(1)

public int numberOfSteps (int num) {
	int steps = 0;
	while (num != 0) {
		if ((num & 1) == 0)
			num >>= 1;
		else
			num--;
		steps++;
	}
	return steps;
}


//Method 2 Recursive
//T: O(n), S: O(n)

public int numberOfSteps(int num) {
	return recurse(num, new int[1]);
}

public int recurse(int num, int[] steps) {
	if (num == 0)
		return steps[0];
	steps[0]++;
	return ((num & 1) == 0) ? recurse(num >> 1, steps) : recurse(num - 1, steps);
}

//Method 2 Recursive2
public int numberOfSteps (int num) {
    if(num==0)return 0;
    return 1 + numberOfSteps(num%2==0?num/2:num-1);
}