PEAKINARRAY - Editorial

editorial
1

Prerequisites:- None

Problem :- Given an array A of size N, find and print all the peak elements in the array. A peak element is one which is strictly greater than any of its adjacent elements.

If there is no peak element in an array, print -1.

Explanation :-

Iterate over each element of the array and print it if the element is greater than its left and right adjacent elements. If you don’t find any such element, print -1.

Solution :-
C++ Solution : -

#include <iostream>
#include <vector>
using namespace std;

int main() {
    int n;
    cin >> n;
    vector<int> A(n);
    
    // Input array elements
    for(int i = 0; i < n; i++) {
        cin >> A[i];
    }
    
    bool hasPeak = false;
    
    for(int i = 0; i < n; i++) {
        if((i == 0 || A[i] > A[i-1]) && (i == n-1 || A[i] > A[i+1])) {
            cout << A[i] << " ";
            hasPeak = true;
        }
    }
    
    if(!hasPeak) {
        cout << "-1";
    }
    
    return 0;
}