Climbing Stairs Problem & Solution
You are climbing a staircase.
It takes n steps to reach the top.
Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?
See the climbing stairs problem on LeetCode.
C++ Solution
#pragma GCC optimize("Ofast")
#pragma GCC optimization("unroll-loops")
static const int _=[](){std::ios::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);return 0;}();
class Solution {
public:
int climbStairs(int n) {
if (n <= 2) {
return n;
}
int result = 0;
int first = 1;
int second = 2;
for (int i = 3; i <= n; ++i) {
int tmp = result;
result = first + second;
first = second;
second = result;
}
return result;
}
};