Ways to repay Loan

                        Ways to repay Loan

                                 


A poor man borrows a sum of N rupees from his neighbour.
 The neighbour is kind enough not to impose any interest on the loan.
The poor man agrees to re-pay the loan by paying back either 1 rupee or 2 rupees to his neighbour. In how many distinct ways can he repay the loan?

Input Format:The first line will contain the value of N which is the loan amount.

Output Format:The first line will contain the number of distinct ways in which the loan can be repaid.Constraints:1 <= N <= 999999

Example Input/Output 1:
Input:
1
Output:
1

Example Input/Output 2:
Input:
2
Output:
2
Explanation:The loan can be re-paid as 1,1 or as 2

Example Input/Output 3:
Input:
5
Output:
8

Explanation:
The loan can be re-paid as
1,1,1,1,1 or
1,1,1,2 or
1,2,2 or
1,1,2,1 or
1,2,1,1 or
2,2,1 or
2,1,2 or
2,1,1,1

Code:

1. #include <iostream>
2. using namespace std;
3. int main(int argc, char** argv)
4. {
5.     long n,a=0,b=1,c=0;
6.     cin>>n;
7.     if(n==1)
8.         cout<<"1";
9.     else{
10.     for(int i=0;i<n;i++)
11.         {
12.             c=a+b;
13.             a=b;
14.             b=c;
15.         }
16.     cout<<c;
17.     }
18. }