70. Climbing Stairs
题目描述
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?
代码实现
class Solution {
public:
int climbStairs(int n) {
if(n < 1)
return 0;
if(n == 1)
return 1;
if(n == 2)
return 2;
int first = 1;
int second = 2;
int result = 0;
for(int i = 3;i <= n; i++){
result = first + second;
first = second;
second =result;
}
return result;
}
};