題目原址

題目描述

You have a total of n coins that you want to form in a staircase shape, where every k-th row must have exactly k coins.

Given n, find the total number of full staircase rows that can be formed.

n is a non-negative integer and fits within the range of a 32-bit signed integer.

Example1：

n = 5

The coins can form the following rows:
¤
¤ ¤
¤ ¤
Because the 3rd row is incomplete, we return 2.

Example2：

n = 8
The coins can form the following rows:
¤
¤ ¤
¤ ¤ ¤
¤ ¤
Because the 4th row is incomplete, we return 3.

解題思路

這個題很簡單，首先第i行有i個元素，找到最後一行滿足第i行有i個元素的行數

AC程式碼

class Solution {
    public int arrangeCoins(int n) {
        int row = 1;
        while(n >= row) {
            n = n - row;
            row ++;
        }
        return row - 1 ;

    }
}