Today I have done leetcode's January LeetCoding Challenge with cpp.

January LeetCoding Challenge 18

Description

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

Solution

constexpr auto table = []{
  array<int, 46> arr{1, 1};
  for(int i = 2; i < 46; ++i) arr[i] = arr[i - 1] + arr[i - 2];
  return arr;
}();
class Solution {
public:
  int climbStairs(int n) {
    return table[n];
  }
};

// Accepted
// 45/45 cases passed (0 ms)
// Your runtime beats 100 % of cpp submissions
// Your memory usage beats 55.72 % of cpp submissions (6 MB)