方法1:动态规划
时间复杂度:$O(n)$
空间复杂度:$O(1)$
解题思路
f(n) = f(n - 1) + f(n - 2)
https://leetcode.cn/problems/climbing-stairs/solution/pa-lou-ti-by-leetcode-solution/
Java 代码
class Solution {
public int climbStairs(int n) {
int p = 0, q = 0, x = 1;
for (int i = 1; i <= n; i ++) {
p = q;
q = x;
x = p + q;
}
return x;
}
}