LeetCode 70: Climbing Stairs

Climbing Stairs

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?

解题思路

class Solution {
public:
int climbStairs(int n) {
if (n <= 2) return n;

vector<int> dp(n, 0);
dp[0] = 1;
dp[1] = 2;
for (int i = 2; i < n; ++i) {
dp[i] = dp[i-1] + dp[i-2];
}

return dp[n-1];
}
};