[Intro] shapeArea

Below we will define an n-interesting polygon. Your task is to find the area of a polygon for a given n.

A 1-interesting polygon is just a square with a side of length 1. An n-interesting polygon is obtained by taking the n - 1-interesting polygon and appending 1-interesting polygons to its rim, side by side. You can see the 1-, 2-, 3- and 4-interesting polygons in the picture below.

func shapeArea(n int) int {
    if n==1{
        return 1
    }
    cover := 1
    for i:=2;i<n+1;i++{
        cover+= i+(i-1)*2+(i-2)
    }
    return cover
}

파이썬이 아니라 Go로 풀었던 문제

 

하지만 정답은 매우 간단했다고 한다.

 

def shapeArea(n):
    return n**2 + (n-1)**2