Given an array of N elements. The task is to check if the array is bitonic or not.
An array is said to be bitonic if the elements in the array are first strictly increasing and then strictly decreasing.
Examples:
Input: arr[] = {-3, 9, 11, 20, 17, 5, 1}
Output: YESInput: arr[] = {5, 6, 7, 8, 9, 10, 1, 2, 11};
Output: NO
Approach:
- Start traversing the array and keep checking if the next element is greater than the current element or not.
- If at any point, the next element is not greater than the current element, break the loop.
- Again start traversing from the current element and check if the next element is less than current element or not.
- If at any point before the end of array is reached, if the next element is not less than the current element, break the loop and print NO.
- If the end of array is reached successfully, print YES.
Below is the implementation of above approach:
C++
// C++ program to check if an array is bitonic#include <bits/stdc++.h>using namespace std;// Function to check if the given array is bitonicint checkBitonic(int arr[], int n){ int i, j; // Check for increasing sequence for (i = 1; i < n; i++) { if (arr[i] > arr[i - 1]) continue; if (arr[i] <= arr[i - 1]) break; } if (i == n - 1) return 1; // Check for decreasing sequence for (j = i + 1; j < n; j++) { if (arr[j] < arr[j - 1]) continue; if (arr[j] >= arr[j - 1]) break; } i = j; if (i != n) return 0; return 1;}// Driver codeint main(){ int arr[] = { 1,2,3 }; int n = sizeof(arr) / sizeof(arr[0]); (checkBitonic(arr, n) == 1) ? cout << "YES" : cout << "NO"; return 0;} |
Java
// Java program to check // if an array is bitonicclass GFG{// Function to check if the // given array is bitonicstatic int checkBitonic(int arr[], int n) { int i, j; // Check for increasing sequence for (i = 1; i < n; i++) { if (arr[i] > arr[i - 1]) continue; if (arr[i] <= arr[i - 1]) break; } if (i == n - 1) return 1; // Check for decreasing sequence for (j = i + 1; j < n; j++) { if (arr[j] < arr[j - 1]) continue; if (arr[j] >= arr[j - 1]) break; } i = j; if (i != n) return 0; return 1;}// Driver Codepublic static void main(String args[]) { int arr[] = { -3, 9, 7, 20, 17, 5, 1 }; int n = arr.length; System.out.println((checkBitonic(arr, n) == 1) ? "YES" : "NO");}}// This code is contributed by Bilal |
Python3
# Python3 program to check if # an array is bitonic or not.# Function to check if the # given array is bitonicdef checkBitonic(arr, n) : # Check for increasing sequence for i in range(1, n) : if arr[i] > arr[i - 1] : continue else : break if i == n-1 : return 1 # Check for decreasing sequence for j in range(i + 1, n) : if arr[j] < arr[j - 1] : continue else : break i = j if i != n - 1 : return 0 return 1# Driver Codeif __name__ == "__main__" : arr = [-3, 9, 7, 20, 17, 5, 1] n = len(arr) if checkBitonic(arr, n) == 1 : print("YES") else : print("NO")# This code is contributed# by ANKITRAI1 |
C#
// C# program to check // if an array is bitonicusing System;class GFG{// Function to check if the // given array is bitonicstatic int checkBitonic(int []arr, int n) { int i, j; // Check for increasing sequence for (i = 1; i < n; i++) { if (arr[i] > arr[i - 1]) continue; if (arr[i] <= arr[i - 1]) break; } if (i == n - 1) return 1; // Check for decreasing sequence for (j = i + 1; j < n; j++) { if (arr[j] < arr[j - 1]) continue; if (arr[j] >= arr[j - 1]) break; } i = j; if (i != n) return 0; return 1;}// Driver Codepublic static void Main() { int []arr = { -3, 9, 7, 20, 17, 5, 1 }; int n = arr.Length; Console.WriteLine(( checkBitonic(arr, n) == 1) ? "YES" : "NO");}}// This code is contributed by Bilal |
PHP
<?php // PHP program to check if // an array is bitonic// Function to check if the // given array is bitonicfunction checkBitonic(&$arr, $n){ // Check for increasing sequence for ($i = 1; $i < $n; $i++) { if ($arr[$i] > $arr[$i - 1]) continue; if ($arr[$i] <= $arr[$i - 1]) break; } if ($i == $n - 1) return 1; // Check for decreasing sequence for ($j = $i + 1; $j < $n; $j++) { if ($arr[$j] < $arr[$j - 1]) continue; if ($arr[$j] >= $arr[$j - 1]) break; } $i = $j; if ($i != $n) return 0; return 1;}// Driver code$arr = array( -3, 9, 7, 20, 17, 5, 1 );$n = sizeof($arr);checkBitonic($arr, $n) == 1 ? print("YES") : print("NO");// This code is contributed by ChitraNayal?> |
Javascript
<script>// Java Script program to check// if an array is bitonic// Function to check if the// given array is bitonicfunction checkBitonic(arr,n){ let i, j; // Check for increasing sequence for (i = 1; i < n; i++) { if (arr[i] > arr[i - 1]) continue; if (arr[i] <= arr[i - 1]) break; } if (i == n - 1) return 1; // Check for decreasing sequence for (j = i + 1; j < n; j++) { if (arr[j] < arr[j - 1]) continue; if (arr[j] >= arr[j - 1]) break; } i = j; if (i != n) return 0; return 1;}// Driver Code let arr = [ -3, 9, 7, 20, 17, 5, 1 ]; let n = arr.length; document.write((checkBitonic(arr, n) == 1) ? "YES" : "NO");// This code is contributed by sravan kumar </script> |
Output
YES
Time Complexity: O(n), As we are traversing the array only once.
Auxiliary Space: O(1), As constant extra space is used.
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