Count of array elements which is smaller than both its adjacent elements

Given an array arr[] of size N, the task is to find the number of valley points in the array.

Valley Point: Any elements of the array is known as a valley point if it is smaller than both its adjacent elements, i.e. arr[i-1] > arr[i] < arr[i+1].

Examples:



Input: arr[] = {3, 2, 5}
Output: 1
Explanation:
There is only one valley point. That is arr[1].

Input: arr[] = {5, 4, 8, 3, 6}
Output: 2
Explanation:
There are two valley points. That is arr[1] and arr[3].

Approach: The idea is to iterate over the array from 1 to N-1 and for each element check for that element is a valley point or not if yes, then increment the count of the valley point by 1.

if (arr[i-1] > arr[i] < arr[i])
     count += 1;

Below is the implementation of the above approach:

Java

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// Java program to count the number
// of valley points in the array
  
import java.io.*;
  
class GFG {
  
    // Function to count the valley points
    // in the given character array
    static int countValleys(int n, int arr[])
    {
        int count = 0, temp = 0;
  
        // Loop to iterate over the elements
        // of the given array
        for (int i = 1; i < n - 1; i++) {
  
            // Condition to check if the given
            // element is a valley point
            if (arr[i - 1] > arr[i]
                && arr[i] < arr[i + 1]) {
                count++;
            }
        }
        return count;
    }
  
    // Driver Code
    public static void main(String[] args)
    {
        int arr[] = { 3, 2, 5 };
        int n = arr.length;
        System.out.println(
            countValleys(n, arr));
    }
}

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Output:

1

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