climbing-stairs.cc

class Solution {
 
public:
 
    int climbStairs(int n) {
        int cache[46] = {0};
        cache[1] = 1;
        cache[2] = 2;
 
        if (n == 1) return 1;
        if (n == 2) return 2;
 
        for (int i = 3; i <= n; i++) {
            cache[i] = cache[i - 1] + cache[i - 2];
        }
 
        return cache[n];
    }
};