# LeetCode 70. Climbing Stairs: Java Solution

## Problem Statement

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

Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?

```
Function Signature (Java):
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

```
public int climbStairs(int n) {
if (n <= 2) {
return n;
}
int oneBefore = 2;
int twoBefore = 1;
int curr = 0;
for (int i = 3; i <= n; i++) {
curr = oneBefore + twoBefore;
twoBefore = oneBefore;
oneBefore = curr;
}
return curr;
}
```