Leetcode Arranging Coins problem solution

In this Leetcode Arranging Coins problem solution 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. we have given the integer n, return the number of complete rows of the staircase you will build.

Problem solution in Python.

class Solution:
    def arrangeCoins(self, n: int) -> int:
        rows = 0
        i = 1
        
        while n >= i:
            n-=i
            rows+=1
            i+=1
               
        return rows

Problem solution in Java.

class Solution {
public int arrangeCoins(int n) {

    long start=1;
    long sum=1;
    while( sum <= n){
        sum+= ++start;
    }
    
    return (int) start-1;
    
}
}

Problem solution in C++.

class Solution {
public:
    int arrangeCoins(int n) {
        long long num=n;
        return (-1+sqrt(1+8*num))/2;
    }
};

Problem solution in C.

int arrangeCoins(int n){
    int k = 1;
    while(k <= n){
        n -= k++;
    }
    return k-1;
}