Skip to content
Related Articles

Related Articles

Check if array can be converted into strictly decreasing sequence
  • Last Updated : 06 May, 2021

Given an array arr[], the task is to check whether given array can be converted into a strictly decreasing sequence with the help of the below operation: 
 

  • Decrease any element(if it is greater than 1) by 1 in one operation

Examples: 
 

Input: arr[] = {11, 11, 11, 11} 
Output : Yes 
Explanation: 
The given sequence can be converted into 
arr[] = {11, 10, 9, 8}
Input: arr[] = {1, 1} 
Output: No 
Explanation: 
The given sequence cannot be converted into strictly decreasing sequence 
 

 

Approach: The idea is to check whether every element of the array is greater than or equal to (N – index of element), because if it is greater than or equal to (N – index of element) that means array can be converted into [N, N-1, N-2, ….1]
Below is the implementation of the above approach: 
 



C++




// C++ implementation to check that
// array can be converted into a
// strictly decreasing sequence
#include <bits/stdc++.h>
using namespace std;
 
// Function to check that array
// can be converted into a
// strictly decreasing sequence
bool check(int* arr, int n)
{
    bool flag = true;
 
    // Loop to check that each element is
    // greater than the (N - index)
    for (int i = 0; i < n; i++) {
 
        // If element is less than (N - index)
        if (arr[i] < n - i) {
            flag = false;
        }
    }
 
    // If array can be converted
    if (flag) {
        return true;
    }
    else {
        return false;
    }
}
 
// Driver Code
int main()
{
    int arr1[] = { 11, 11, 11, 11 };
    int n1 = sizeof(arr1) / sizeof(arr1[0]);
 
    // Function calling
    if (check(arr1, n1)) {
        cout << "Yes" << endl;
    }
    else {
        cout << "No" << endl;
    }
}

Java




// Java implementation to check that
// array can be converted into a
// strictly decreasing sequence
class GFG{
 
// Function to check that array
// can be converted into a
// strictly decreasing sequence
static boolean check(int []arr, int n)
{
    boolean flag = true;
 
    // Loop to check that each element is
    // greater than the (N - index)
    for (int i = 0; i < n; i++)
    {
 
        // If element is less than (N - index)
        if (arr[i] < n - i)
        {
            flag = false;
        }
    }
 
    // If array can be converted
    if (flag)
    {
        return true;
    }
    else
    {
        return false;
    }
}
 
// Driver Code
public static void main(String[] args)
{
    int arr1[] = { 11, 11, 11, 11 };
    int n1 = arr1.length;
 
    // Function calling
    if (check(arr1, n1))
    {
        System.out.print("Yes" + "\n");
    }
    else
    {
        System.out.print("No" + "\n");
    }
}
}
 
// This code is contributed by amal kumar choubey

Python3




# Python3 implementation to check that
# array can be converted into a
# strictly decreasing sequence
 
# Function to check that array
# can be converted into a
# strictly decreasing sequence
def check(arr, n):
 
    flag = True;
 
    # Loop to check that each element
    # is greater than the (N - index)
    for i in range(n):
         
        # If element is less than (N - index)
        if (arr[i] < n - i):
            flag = False;
             
    # If array can be converted
    if (flag):
        return True;
    else:
        return False;
 
# Driver Code
if __name__ == '__main__':
     
    arr1 = [ 11, 11, 11, 11 ];
    n1 = len(arr1);
 
    # Function calling
    if (check(arr1, n1)):
        print("Yes");
    else:
        print("No");
 
# This code is contributed by sapnasingh4991

C#




// C# implementation to check that
// array can be converted into a
// strictly decreasing sequence
using System;
 
class GFG{
 
// Function to check that array
// can be converted into a
// strictly decreasing sequence
static bool check(int []arr, int n)
{
    bool flag = true;
 
    // Loop to check that each element is
    // greater than the (N - index)
    for(int i = 0; i < n; i++)
    {
 
       // If element is less than (N - index)
       if (arr[i] < n - i)
       {
           flag = false;
       }
    }
 
    // If array can be converted
    if (flag)
    {
        return true;
    }
    else
    {
        return false;
    }
}
 
// Driver Code
static public void Main(String[] args)
{
    int []arr1 = { 11, 11, 11, 11 };
    int n1 = arr1.Length;
 
    // Function calling
    if (check(arr1, n1))
    {
        Console.Write("Yes" + "\n");
    }
    else
    {
        Console.Write("No" + "\n");
    }
}
}
 
// This code is contributed by 29AjayKumar
Output: 
Yes

 

Attention reader! Don’t stop learning now. Get hold of all the important DSA concepts with the DSA Self Paced Course at a student-friendly price and become industry ready.  To complete your preparation from learning a language to DS Algo and many more,  please refer Complete Interview Preparation Course.

In case you wish to attend live classes with industry experts, please refer Geeks Classes Live and Geeks Classes Live USA

My Personal Notes arrow_drop_up
Recommended Articles
Page :