leetcode

0 // memorization approach

1 class Solution {

2 public:

3 int minCostClimbingStairs(vector<int> &cost) {

4 vector<int> vec(cost.size() + 2);

5 for (int i = 2; i <= cost.size(); i++)

6 vec[i] = min(vec[i - 1] + cost[i - 1], vec[i - 2] + cost[i - 2]);

7 return vec[cost.size()];

8 }

9 };

10

11 // optimized, memorize only the previous two values

12 class Solution {

13 public:

14 int minCostClimbingStairs(vector<int> &cost) {

15 int first = cost[0], second = cost[1];

16 for (int i = 2; i < cost.size(); i++) {

17 int crnt = cost[i] + min(first, second);

18 first = second;

19 second = crnt;

20 }

21 return min(first, second);

22 }

23 };