题解 | 每日温度

class Solution {
public:
    vector<int> temperatures(vector<int>& dailyTemperatures) {
        int size = dailyTemperatures.size();
        vector<int> ans(size);
        stack<int> stk;
		//从后往前遍历，栈往里单调递增
        for(int i=size-1; i>=0; i--){
            while(!stk.empty() && dailyTemperatures[i] >= dailyTemperatures[stk.top()]){
                stk.pop();
            }
            if(!stk.empty()){
                ans[i] = stk.top() - i;
            }
            stk.push(i);
        }

        return ans;
    }
};