70.md

70. Climbing Stairs

Description

You are climbing a stair case. It takes n steps to reach to the top.

Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?

Note: Given n will be a positive integer.

Thinking Process

1. Simple dynamic programming

Code

public class Solution {
    public int climbStairs(int n) {
        int[] ways = new int[n+1];
        ways[0] = 1;
        ways[1] = 1;
        for(int i = 2; i < n+1; i++){
            ways[i] = ways[i-1] + ways[i-2];
        }
        return ways[n];
    }
}