441. Arranging Coins（LeetCode）

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.

class Solution {
public:
	int arrangeCoins(int n) {
		if (n == 0)
			return 0;
		long long sum = 0;
		int count = 0;
		for (int i = 1; i <= n; i++)
		{
			sum += i;
			if (sum <= n)
				count++;
			else
				break;
		}
		return count;
	}
};