题目
image.png
分析
斐波那契数列。
代码
class Solution {
public:
int climbStairs(int n) {
int first = 1, second = 2;
if (n == 1){
return first;
}else if (n == 2){
return second;
}else{
int res;
for (int i = 3; i <= n; i++){
res = first + second;
first = second;
second = res;
}
return res;
}
}
};
