LeetCode 70. 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?

Note: Given n will be a positive integer.

解法：利用DP动态规划，由于dp[i] = dp[i-2] + dp[i-1]

class Solution {

public:
    int climbStairs(int n) {
        if (n == 1) return 1;
        int dp[n+1];
        dp[1] = 1;
        dp[2] = 2;
        for (int i = 3; i <= n ; i++) {
            dp[i] = dp[i-1] + dp[i-2];
        }
        return dp[n];
    }
};