TriCoin Problem java

help
1

Hi I did the solution using binary search but failed test cases.
Here is my code.

Note : Code is working fine in my ide when giving inputs;
eg : input (coins) = 21 → output (height) = 6

public class CoinsTraingle {

// function 2
public static int getCoins(int height) {

    int coins = 0;

    // formula for getting sum of n natural no;
    coins = height * (height + 1) / 2;
    return coins;
}

// function 1
public static int heightOfTraingle(int coins) {

    // Edge case: Triangle cannot be formed with 0 or 1 coin
    if (coins <= 1) {
        return 0;
    }

    int start = 0;
    int end = coins;

    int mid = start + (end - start) / 2;

    int ans = -1;

    while (start < end) {

        // getCoins fn that takes height param
        if (getCoins(mid) == coins) {
            return mid;
        }

        if (getCoins(mid) < coins) {
            ans = mid;
            start = mid + 1;
        } else {
            end = mid;
        }

        mid = start + (end - start) / 2;
    }
    return ans;
}

public static void main(String[] args) throws java.lang.Exception {
    // your code goes here
    Scanner sc = new Scanner(System.in);

    // taking input
    System.out.println("Enter no of coins > 1:");
    int coins = sc.nextInt();

    // giving output
    System.out.print("Max possible height of traingle is ");
    System.out.println(heightOfTraingle(coins));
    sc.close();

}

}