Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
Find the maximum element in an array which is first increasing and then decreasing in C++
Suppose we have one array, which is initially increasing then decreasing. We have to find the max value in the array. So if the array elements are like A = [8, 10, 20, 80, 100, 250, 450, 100, 3, 2, 1], then output will be 500.
We can use the binary search to solve this. There are three conditions −
- When mid is greater than both of its adjacent elements, then mid is maximum
- If mid is greater than the next element, but smaller than previous element, then max lies on the left side of mid.
- If mid element is smaller than the next element, but greater than previous element, then max lies on the right side of mid.
Example
#include<iostream>
using namespace std;
int getMaxElement(int array[], int left, int right) {
if (left == right)
return array[left];
if ((right == left + 1) && array[left] >= array[right])
return array[left];
if ((right == left + 1) && array[left] < array[right])
return array[right];
int mid = (left + right)/2;
if ( array[mid] > array[mid + 1] && array[mid] > array[mid - 1])
return array[mid];
if (array[mid] > array[mid + 1] && array[mid] < array[mid - 1])
return getMaxElement(array, left, mid-1);
else
return getMaxElement(array, mid + 1, right);
}
int main() {
int array[] = {8, 10, 20, 80, 100, 250, 450, 100, 3, 2, 1};
int n = sizeof(array)/sizeof(array[0]);
cout << "The maximum element is: " << getMaxElement(array, 0, n-1);
}Output
The maximum element is: 450
Updated on: 17-Dec-2019
184 Views
Advertisements