# [Solved] 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.

## Question

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:

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

Example 2:

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

Constraints:

• `1 <= n <= 231 - 1`

## Python Solution

```class Solution:
def arrangeCoins(self, n: int) -> int:
if n==1:
return 1
l=0
r=n//2 + 1
while l<=r:
m = l+(r-l)//2
x = (m*(m+1)//2)
if x==n:
return(m)
elif x<n:
l = m+1
else:
r=m-1
return(l-1)``` ##### Abhishek Sharma

Started my Data Science journey in my 2nd year of college and since then continuously into it because of the magical powers of ML and continuously doing projects in almost every domain of AI like ML, DL, CV, NLP.

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