LEETCODEEasy
Climbing Stairs
You are climbing a staircase. It takes n steps to reach the top.
Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?
Example 1:
Input: n = 2 Output: 2 Explanation: There are two ways to climb to the top. 1. 1 step + 1 step 2. 2 steps
Example 2:
Input: n = 3 Output: 3 Explanation: There are three ways to climb to the top. 1. 1 step + 1 step + 1 step 2. 1 step + 2 steps 3. 2 steps + 1 step
Constraints:
1 <= n <= 45
풀이 TypeScript
function climbStairs(n: number): number {
let prev = 1, curr = 1;
for (let i = 2; i <= n; i++) {
[prev, curr] = [curr, prev + curr];
}
return curr;
}
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