class Solution {
public:
    vector<int> dailyTemperatures(vector<int>& temperatures) {
        stack<int> monoStk;
        int len = temperatures.size();
        vector<int> res(len);
        for(int i = 0; i < len; i++) {
            while(!monoStk.empty() && temperatures[monoStk.top()] < temperatures[i]) {
                int top = monoStk.top();
                res[top] = i - top;
                monoStk.pop();
            }
            monoStk.push(i);
        }
        return res;
    }
};

class Solution {
public:
    int climbStairs(int n) {
        int a=1,b=2;
        if(n<2) return 1; 
        for(int i = 2; i <n ; i++) {
            int c = a+b;
            a=b;
            b=c;
        }
        return b;
    }
};