ValidMountain.java

package LeetcodePractice;

public class ValidMountain {
     public boolean validMountainArray(int[] arr) {
        int n = arr.length;
        if (n < 3) return false;

        int i = 0;

       
        while (i + 1 < n && arr[i] < arr[i + 1]) {
            i++;
        }

        
        if (i == 0 || i == n - 1) return false;

       
        while (i + 1 < n && arr[i] > arr[i + 1]) {
            i++;
        }

        
        return i == n - 1;
    }

    public static void main(String[] args) {
        ValidMountain sol = new ValidMountain();
        System.out.println(sol.validMountainArray(new int[]{2,1}));        
        System.out.println(sol.validMountainArray(new int[]{3,5,5}));     
        System.out.println(sol.validMountainArray(new int[]{0,3,2,1}));  
    }
}