# LeetCode 70. Climbing Stairs: C++ Solution

## Problem Statement

You are climbing a staircase. It takes n steps to reach to the top.

You can only climb 1 or 2 steps at a time.

Design an algorithm to find how many distinct ways can you climb to the top.

```
Function Signature (C++):
int climbStairs(int n)
Inputs:
n = 2
Outputs:
2
You can get to step 2 two different ways.
1 step + 1 step
2 step
Inputs:
n = 3
Outputs:
3
You can get to step 2 two different ways.
1 step + 1 step + 1 step
2 step + 1 step
1 step + 2 step
```

## TL;DR Code Solution

```
int climbStairs(int n) {
if (n < 3) {
return n;
}
int twoBefore = 1;
int oneBefore = 2;
int result;
for (int i = 3; i <= n; i++) {
result = oneBefore + twoBefore;
twoBefore = oneBefore;
oneBefore = result;
}
return result;
}
```