441_Arranging Coins

/*Runtime: 1 ms, faster than 100.00% of Java online submissions for Arranging Coins.
Memory Usage: 37.1 MB, less than 34.64% of Java online submissions for Arranging Coins.*/

class Solution {
    public int arrangeCoins(int n) {
        
    return (int) ((Math.sqrt(1 + 8.0 * n) - 1) / 2);  
        
    }
}



/*using for loop
Runtime: 8 ms, faster than 28.90% of Java online submissions for Arranging Coins.
Memory Usage: 36.5 MB, less than 95.78% of Java online submissions for Arranging Coins.

class Solution {
    public int arrangeCoins(int n) {
        if(n==0)
            return 0;
        
        int temp=n/2;
        temp++;
     for(int i=1;i<=temp;i++){
         n=n-i;
         if(n<0)
             return i-1;
         if(n==0)
             return i;
     }  
        return 0;
        
    }
   
}
*/



/*Using recursion
Runtime: 58 ms, faster than 5.02% of Java online submissions for Arranging Coins.
Memory Usage: 41.1 MB, less than 5.04% of Java online submissions for Arranging Coins.

class Solution {
    public int arrangeCoins(int n) {
      if(n==0)
          return 0;
        return helper(n,1,0); 
    }
    
    public int helper(int n,int c,int count) {
                if(n<0)
                    return count-1;
                if(n==0)
                    return count;
        
        return helper(n-c,c+1,count+1);
        
    }
}
*/