Climbing Stairs @leetcode

http://oj.leetcode.com/problems/climbing-stairs/

不要在一个CASE里重复计算

int res[10000]={0};
class Solution {
public:
    int climbStairs(int n) {
        // IMPORTANT: Please reset any member data you declared, as
        // the same Solution instance will be reused for each test case.
        if(n <= 0)
            return 0;
        if(n == 1)
            return 1;
        if(n == 2)
            return 2;
        if(n == 3)
            return 3;
        if(n<10000&&res[n]!=0)
            return res[n];
        if(n-1<10000)
        {
            res[n-1] = climbStairs(n-1);
        }
        if(n-2<10000)
        {
            res[n-2] = climbStairs(n-2);
        }
        return res[n-1]+res[n-2];
    }
};