leetcode 070 —— 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?

思路：一维简单动态规划

class Solution {
public:
	int climbStairs(int n) {
		vector<int> dp(n, 0);
		if (n < 2)
			return n;
		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];
	}
};