Climbing stairs with 3 moves

There are n stairs, and a person standing at the bottom can climb either 1 stair, 2 stairs or 3 staris at a time, count the number of ways that a person can reach at the top.

Hint

Imagine you're climbing a staircase. You can choose to climb 1, 2, or 3 steps at a time. To find the total number of ways to climb the entire staircase, you can break it down:

• If the staircase is small (1, 2, or 3 steps): You can directly count the possible ways.

• If the staircase is larger:

  • Count the ways to climb if you take 1 step first, and then add that to...
  • Count the ways to climb if you take 2 steps first, and then add that to...
  • Count the ways to climb if you take 3 steps first.

  This recursive approach efficiently calculates the total number of climbing possibilities.

• Python
• Javascript
•  Run

def climb(n):
  if n < 0:
    return 0

  if n == 1:
    return 1

  if n == 2:
    return 2

  if n == 3:
    return 4
  
  return climb(n - 1) + climb(n - 2) + climb(n - 3)

n = 5

print(climb(n))

function climb(n) {
  if (n < 0) {
    return 0;
  }

  if (n === 1) {
    return 1;
  }

  if (n === 2) {
    return 2;
  }

  if (n === 3) {
    return 4;
  }
  
  return climb(n - 1) + climb(n - 2) + climb(n - 3);
}

const n = 5;

console.log(climb(n));