valid mountain array leetcode

/*Valid Mountain Array

Given an array of integers arr, return true if and only if it is a valid mountain array.

Recall that arr is a mountain array if and only if:

    arr.length >= 3
    There exists some i with 0 < i < arr.length - 1 such that:
        arr[0] < arr[1] < ... < arr[i - 1] < arr[i]
        arr[i] > arr[i + 1] > ... > arr[arr.length - 1]
*/

class Solution {
    public boolean validMountainArray(int[] arr) {
       
        if (arr.length < 3) {
            return false;
        }
        
        boolean isValley = false;
        boolean hasIncreased = false;
        int prev = arr[0];
        
        for(int i = 1; i < arr.length; i++) {
             if (prev == arr[i]) {
                return false;
            }
            
            if (!isValley) {
           
                if (prev > arr[i]) {
                    isValley = true;
                }
                
                if (prev < arr[i]) {
                    hasIncreased = true;
                }
            }
            
            if (isValley) {
                if (prev < arr[i]) {
                    return false;
                }
            }
            
            prev = arr[i];
            
        }
        
        return isValley && hasIncreased;
    }
}