Any help? I think my solution meets the criteria

Question about the task

Under discussion

I believe this solution does run in a linear fashion, 1 additional calculation for each step added. But I can not get this task to pass the last criteria. Any help?

A boy runs up a flight of stairs consisting of n steps; in 1 bound, he can move up one, two or three steps.

Implement the numberOfPossibleAscents(int n) method, which should return the number of ways the boy can ascend an entire flight of stairs consisting of n steps.

P.S. If the flight of stairs consists of 0 steps, the method should return 1. For n < 0, return 0.

Requirements:

The numberOfPossibleAscents method should return the number of ways to ascend a flight of stairs consisting of n steps.
The numberOfPossibleAscents method should return 1 for n = 0.
The numberOfPossibleAscents method should return 0 for n < 0.
The numberOfPossibleAscents method must have linear running time.

package com.codegym.task.task39.task3904; import org.apache.commons.collections4.functors.PredicateTransformer; import java.util.Arrays; /* Stairs */ public class Solution { private static int n = 70; public static void main(String[] args) { System.out.println("The number of possible ascents for " + n + " steps is: " + numberOfPossibleAscents(n)); } public static long numberOfPossibleAscents(int n) { if (n < 0) return 0; if (n == 0) return 1; if (n == 1) return 1; int[] res = new int[n + 1]; res[0] = 1; res[1] = 1; res[2] = 2; for (int i = 3; i <= n; i++) res[i] = res[i - 1] + res[i - 2] + res[i - 3]; return res[n]; } }

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Seb

Level 41 , Crefeld, Germany

29 February 2020, 13:32

Use long instead of int for your variables in the numberOfPossibleAscents method... ;-) :-)