shortestStepsToNum.md

Shortest steps to a number

Summary:

• Given a number, num, return the shortest amount of steps it would take from 1, to land exactly on that number.

Description:

A step is defined as either:

• Adding 1 to the number: num += 1
• Doubling the number: num *= 2

You will always start from the number 1 and you will have to return the shortest count of steps it would take to land exactly on that number.

Examples:

num == 3 would return 2 steps:

1 -- +1 --> 2:        1 step
2 -- +1 --> 3:        2 steps

2 steps

num == 12 would return 4 steps:

1 -- +1 --> 2:        1 step
2 -- +1 --> 3:        2 steps
3 -- x2 --> 6:        3 steps
6 -- x2 --> 12:       4 steps

4 steps

num == 16 would return 4 steps:

1 -- +1 --> 2:        1 step
2 -- x2 --> 4:        2 steps
4 -- x2 --> 8:        3 steps
8 -- x2 --> 16:       4 steps

4 steps

Solution:

function shortestStepsToNum(num) {
  let steps = 0;
  while (num > 1) {
    num % 2 === 0 ? (num /= 2) : num--;
    steps++;
  }
  return steps;
}
console.log(shortestStepsToNum(1)); // 0 
console.log(shortestStepsToNum(12)); // 4
console.log(shortestStepsToNum(16)); // 4
console.log(shortestStepsToNum(71)); // 9