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. .

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].

Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Approach: The idea is to iterate over the array from 1 to 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:

 `// C++ program to count the number ` `// of valley points in the array ` `#include ` `using` `namespace` `std; ` ` `  `// Function to count the valley points ` `// in the given character array ` `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 ` `int` `main() ` `{ ` `    ``int` `arr[] = { 3, 2, 5 }; ` `    ``int` `n = ``sizeof``(arr) / ``sizeof``(arr[0]); ` `     `  `    ``cout << countValleys(n, arr); ` `} ` ` `  `// This code is contributed by Surendra_Gangwar `

 `// 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)); ` `    ``} ` `} `

 `# Python3 program to count the number ` `# of valley points in the array ` ` `  `# Function to count the valley points ` `# in the given character array ` `def` `countValleys(n, arr): ` ` `  `    ``count ``=` `0``; temp ``=` `0``; ` ` `  `    ``# Loop to iterate over the  ` `    ``# elements of the given array ` `    ``for` `i ``in` `range``(``1``, n): ` ` `  `        ``# Condition to check if the given ` `        ``# element is a valley point ` `        ``if` `(arr[i ``-` `1``] > arr[i] ``and` `            ``arr[i] < arr[i ``+` `1``]): ` ` `  `            ``count ``+``=` `1``; ` ` `  `    ``return` `count; ` ` `  `# Driver Code ` `arr ``=` `[ ``3``, ``2``, ``5` `]; ` `n ``=` `len``(arr); ` `     `  `print``(countValleys(n, arr)); ` ` `  `# This code is contributed by Code_Mech `

 `// C# program to count the number ` `// of valley points in the array ` `using` `System; ` `class` `GFG{ ` ` `  `// Function to count the valley points ` `// in the given character array ` `static` `int` `countValleys(``int` `n, ``int` `[]arr) ` `{ ` `    ``int` `count = 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() ` `{ ` `    ``int` `[]arr = { 3, 2, 5 }; ` `    ``int` `n = arr.Length; ` `    ``Console.Write(countValleys(n, arr)); ` `} ` `} ` ` `  `// This code is contributed by Code_Mech `

Output:
```1
```

Blockchain Enthusiast

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.

Improved By : SURENDRA_GANGWAR, Code_Mech

Article Tags :
Practice Tags :