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?

思路：就是斐波那契数列

class Solution {
public:
int climbStairs(int n) {
//就是斐波那契数列
if(n < 1)
{
return 0;
}
if(n == 1)
{
return 1;
}
if(n == 2)
{
return 2;
}

int stepPre = 1;
int stepLater = 2;
int result = 0;
for(int i = 3;i<=n;i++)
{
result = stepPre + stepLater;
stepPre = stepLater;
stepLater = result;
}
return result;

}
};