Day 33: Chicks in a Zoo

/*
Chicks in a Zoo

Initially, the zoo have a single chick. A chick gives birth to 2 chicks every day and the life expectancy of a chick is 6 days. Zoo officials want to buy food for chicks so they want to know the number of chicks on an Nth day. Help the officials with this task.
 

Example 1:

Input: N = 2 
Output: 3
Explanation: First day there is only 1 chick.
On second day total number of chicks = 3. 
Example 2:

Input: N = 3
Output: 9
Explanation: First day there is only 1 chick.
On second day total number of chicks = 3.
On third day total number of chicks = 9
 

Your Task:
You don't need to read or print anything, Your task is to complete the function NoOfChicks() which takes N as the input parameter and returns the total no. of chicks on the Nth day.
 

Expected Time Complexity: O(N)
Expected Space Complexity: O(N)
 

Constraints:
1 <= N <= 35
*/

//{ Driver Code Starts
//Initial Template for Java

import java.util.*;
import java.lang.*;
import java.io.*;
class GFG
{
    public static void main(String[] args) throws IOException
    {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int T = Integer.parseInt(br.readLine().trim());
        while(T-->0)
        {
            int N = Integer.parseInt(br.readLine().trim());
            Solution obj = new Solution();
            long ans = obj.NoOfChicks(N);
            System.out.println(ans);
        }
    }
}

// } Driver Code Ends


//User function Template for Java

class Solution
{
    public long NoOfChicks(int N)
    {
         long temp=1;
        long ans=1;
        long arr[]=new long[N];
        boolean flag=false;
        arr[0]=ans;
        int ind=0;
        for(int i=1;i<N;i++){
            temp++;
            if(temp%7==0 || flag){
                flag=true;
                ans-=arr[ind++];
            }
            long val=ans*2;
            arr[i]=val;
            ans+=val;
        }
        return ans;
    }
}