739. Daily Temperatures

class Solution(object):
    def dailyTemperatures(self, temperatures):
        ans=[0]
        l=len(temperatures)
        list1=[l-1]
        top=0
        for i in range(l-2,-1,-1):
            if temperatures[i]<temperatures[list1[-1]]:
                ans.append(list1[-1]-i)
                list1.append(i)
                top+=1
            else:
                while top>=0 and temperatures[list1[top]]<=temperatures[i]:
                    top-=1
                    list1.pop()
                if top<0:
                    ans.append(0)
                else:
                    ans.append(list1[top]-i)
                
                list1.append(i)
                top+=1
        return ans[::-1]