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70. Climbing Stairs
Easy
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
Solution
function climbStairs(n: number, memo: Record<string, number> = {}): number {
if (n in memo) return memo[n]
if (n === 0) return 1
if (n < 0) return 0
memo[n] = climbStairs(n - 1, memo) + climbStairs(n - 2, memo)
return memo[n]
}
export { climbStairs }