[LeetCode/Kotlin]Easy - 441. Arranging Coins

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문제

You have n coins and you want to build a staircase with these coins. The staircase consists of k rows where the ith row has exactly i coins. The last row of the staircase may be incomplete.

Given the integer n, return the number of complete rows of the staircase you will build.

Example 1:

!https://assets.leetcode.com/uploads/2021/04/09/arrangecoins1-grid.jpg

Input: n = 5
Output: 2
Explanation: Because the 3rd row is incomplete, we return 2.

Example 2:

!https://assets.leetcode.com/uploads/2021/04/09/arrangecoins2-grid.jpg

Input: n = 8
Output: 3
Explanation: Because the 4th row is incomplete, we return 3.

Constraints:

• 1 <= n <= 231 - 1

 

풀이

나의 풀이법

풀이 접근 과정

그냥 칸을 늘려주면서 coin 개수를 빼주면 된다고 생각했다.

 

최종 소스코드

class Solution {
    fun arrangeCoins(n: Int): Int {
        var space = 1
        var coins = n

        while (coins >= space) {
            coins -= space
            space++
        }

        return space-1
    }
}

 

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Comment

5분도 안 걸린 짧은 풀이