Error
|
|
---|---|
@Ibrahim Nash | 6420 |
@blackshadows | 6376 |
@mb1973 | 5594 |
@Quandray | 5231 |
@akhayrutdinov | 5111 |
@saiujwal13083 | 4510 |
@sanjay05 | 3762 |
@kirtidee18 | 3673 |
@marius_valentin_dragoi | 3522 |
@sushant_a | 3459 |
@verma_ji | 3412 |
Complete Leaderboard | |
|
|
@codersgroup18 | 783 |
@Manikanta punnam | 605 |
@sriramgoparaju99 | 582 |
@rdakka | 534 |
@praveenbgp6 | 529 |
@prankursharma31 | 518 |
@yashkaril4 | 517 |
@purohitmn02 | 467 |
@sonamnigam1999 | 443 |
@sonamkumari63928 | 441 |
@shubhamstudent5 | 433 |
Complete Leaderboard |
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 matter).
Example 1:
Input: n = 4 Output: 5 Explanation: You can reach 4th stair in 5 ways. Way 1: Climb 2 stairs at a time. Way 2: Climb 1 stair at a time. Way 3: Climb 2 stairs, then 1 stair and then 1 stair. Way 4: Climb 1 stair, then 2 stairs then 1 stair. Way 5: Climb 1 stair, then 1 stair and then 2 stairs.
Example 2:
Input:
n = 10
Output: 89
Explanation:
There are 89 ways to reach the 10th stair.
Your Task:
Complete the function countWays() which takes the top stair number m as input parameters and returns the answer % 10^9+7.
Expected Time Complexity : O(n)
Expected Auxiliary Space: O(1)
Constraints:
1 <= n <= 105
We strongly recommend solving this problem on your own before viewing its editorial. Do you still want to view the editorial?
Yes