leetcodeOJ 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.

//思路：典型的动态规划题
//递推式：ans
= ans[n-1] + ans[n-2]
class Solution {
public:
int climbStairs(int n) {
if(n <= 0)
return 1;
int ans[n+1] = {0};
ans[0] = 1;
ans[1] = 1;
for(int i = 2; i < n+1; i++){
ans[i] = ans[i-1] + ans[i-2];
}
return ans
;
}
};