CheckNumbersequence.cpp

// You are given S, a sequence of n integers i.e. S = s1, s2, ..., sn. Compute if it is possible to split S into two parts : s1, s2, ..., si and si+1, si+2, ….., sn (0 <= i <= n) in such a way that the first part is strictly decreasing while the second is strictly increasing one.
// Note : We say that x is strictly larger than y when x > y.
// So, a strictly increasing sequence can be 1 4 8. However, 1 4 4 is NOT a strictly increasing sequence.

// That is, in the sequence if numbers are decreasing, they can start increasing at one point. 
// Thereafter, they cannot decrease at any point further.
// Sequence made up of only increasing numbers or only decreasing numbers is a valid sequence. 
// So, in both the cases, print true.

// You just need to print true/false. No need to split the sequence.
// Input format :
// Line 1 : Integer 'n'
// Line 2 and Onwards : 'n' integers on 'n' lines(single integer on each line)
// Output Format :
// "true" or "false" (without quotes)
// Constraints :
// 1 <= n <= 10^7
// Sample Input 1 :
// 5
// 9
// 8
// 4
// 5
// 6
// Sample Output 1 :
// true

#include<iostream>
using namespace std;

int main() {
    int n;
    cin >> n;
    int prev;
    cin >> prev;
    int count = 2, current;
    bool isDec = true; 
    while(count <= n) {
        cin >> current;
        if(current == prev) {
            cout << "false";
            return 0;
        } 
        count++;
        if(current < prev) { 
            if(isDec == false) {
                cout << "false";
                return 0;
            }
        }
        else {
            if(isDec == true) {
                isDec = false;
            }
        }
        prev = current;
    }
    cout << "true";
}