_441.java

package com.fishercoder.solutions;

/**
 * 441. Arranging Coins
 *
 * 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.

 Example 1:

 n = 5

 The coins can form the following rows:
 ¤
 ¤ ¤
 ¤ ¤

 Because the 3rd row is incomplete, we return 2.


 Example 2:

 n = 8

 The coins can form the following rows:
 ¤
 ¤ ¤
 ¤ ¤ ¤
 ¤ ¤

 Because the 4th row is incomplete, we return 3.*/
public class _441 {

    public static class Solution1 {
        public int arrangeCoins(int n) {
            if (n < 2) {
                return n;
            }
            int row = 0;
            int count = 0;
            long sum = 0;
            while (sum < n) {
                row += 1;
                sum += row;
                count++;
            }
            if (sum == n) {
                return count;
            }
            return count - 1;
        }
    }

}