70. Climbing Stairs爬樓梯問題
1.問題描述
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?
在爬樓梯時,每次可向上走1階臺階或2階臺階,問有n階樓梯有多少種上樓的方式?
C++
class Solution {
public:
int climbStairs(int n) {
vector<int> dp(n+3, 0);
dp[1] = 1;
dp[2] = 2;
for(int i=3; i<=n; i++) {
dp[i] = dp[i-1] + dp[i-2];
}
return dp[n];
}
};