Climbing Stairs, Leetcode 解题笔记

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?

明显是一维动态规划题,规律也很好找,就是steps[n] = steps[n-1] + steps[n-2]。

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