[LeetCode] Climbing Stairs

http://oj.leetcode.com/submissions/detail/1508385/

最最简单的dp

class Solution {
public:
    int flag[1000001] = {0};
    int f(int n) {
        if (flag[n] != 0) return flag[n];
        if (1 == n) {
            return 1;
        } else if (2 == n) {
            return 2;
        } else {
            flag[n] = f(n - 1) + f(n - 2) ;
            return flag[n];
        }
    }
    
    int climbStairs(int n) {
        memset(flag,0, 1000001);
        return f(n);
    }
};