http://oj.leetcode.com/submissions/detail/1508385/
最最简单的dp
1 class Solution { 2 public: 3 int flag[1000001] = {0}; 4 int f(int n) { 5 if (flag[n] != 0) return flag[n]; 6 if (1 == n) { 7 return 1; 8 } else if (2 == n) { 9 return 2; 10 } else { 11 flag[n] = f(n - 1) + f(n - 2) ; 12 return flag[n]; 13 } 14 } 15 16 int climbStairs(int n) { 17 memset(flag,0, 1000001); 18 return f(n); 19 } 20 };