LeetCode 746 Min Cost Climbing Stairs - Problem Statement

You've seen how to count paths. Now I'll show you how to improve cost. In Min Cost Climbing Stairs (LeetCode $746$), each step has a cost[i] you pay when leaving it.

You can start at step $0$ or $1$, and climb $1$ or $2$ steps at a time. Goal: reach the top (past the last step) with minimum total cost. Example: cost = [10, 15, 20]. Starting at index $1$ costs $15$, then jump $2$ past the last step, total $15$. Starting at index $0$ costs $10$, then step to index $2$ costs $20$, total $30$. Best answer: $15$.