Count ways to N'th Stair(Order does not matter)

PROBLEM :

There are n stairs, a person standing at the bottom wants to reach the top. The person can climb either 1 stair or 2 stairs at a time. Count the number of ways, the person can reach the top (order does not matter). Order does not matter means for n=4 {1 2 1},{2 1 1},{1 1 2} are considered same.

Input:
The first line contains an integer 'T' denoting the total number of test cases. In each test cases, an integer N will be given.


Output:
Print number of possible ways to reach Nth stair.


Constraints:
1<=T<=1000
1<=N<=100

Example:

Input:
1
4

Output:
3

--------------------------------------------------------------------------------
SIMPLE c++ IMPLEMENTATION :
--------------------------------------------------------------------------------

#include<iostream>
using namespace std;
long long Count_nth_stair(long long ) ;
int main()
 {
int t ;
long long no ;
cin>>t ;
while(t--)
{
   cin>>no ;
 
   no=Count_nth_stair(no) ;
   cout<<no<<endl ;
}
return 0;
}

long long Count_nth_stair(long long no)
{
    long long arr[no+1]={0} ;
    int i ;
   
    arr[0]=1 ;
    for(i=1;i<=no;i++)
        arr[i]=arr[i]+arr[i-1] ;
       
    for(i=2;i<=no;i++)
        arr[i]=arr[i]+arr[i-2] ;

    return arr[no] ;
}

---------------------------------------------------------------------------------

Comments

  1. Hit3 July 2019 at 00:13

    cout<<(n/2)+1<<endl;

    ReplyDelete
  2. Amit Kumar3 July 2019 at 14:04

    Hi @Hitesh, try out your solution here: https://practice.geeksforgeeks.org/problems/count-ways-to-reach-the-nth-stair/0

    ReplyDelete

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