739. Daily temperatures

Daily Temperatures - LeetCode

Given a list of daily temperatures temperatures, return a list such that, for each day in the input, tells you how many days you would have to wait until a warmer temperature. If there is no future day for which this is possible, put 0 instead. For example, given the list of temperatures temperatures = [73, 74, 75, 71, 69, 72, 76, 73], your output should be [1, 1, 4, 2, 1, 1, 0, 0]. Note: The length of temperatures will be in the range [1, 30000]. Each temperature will be an integer in the range [30, 100].

  • code
class Solution:
    def dailyTemperatures(self, temperatures: List[int]) -> List[int]:
        res = [0] * len(temperatures)
        stack = []
        
        for i, t in enumerate(temperatures):
            
            while stack and t > temperatures[stack[-1]]:
                lasti = stack.pop()
                res[lasti] = i - lasti
                
            stack.append(i)
                
        return res  
  • code O(N), O(1)
class Solution:
    def dailyTemperatures(self, temperatures: List[int]) -> List[int]:
        res = [0] * len(temperatures)
        hottest = 0
        
        for i in range(len(temperatures)-1, -1, -1):
            if temperatures[i] >= hottest: # not only >
                hottest = temperatures[i]
                continue
            day = 1
            while temperatures[i + day] <= temperatures[i]:
                day += res[i + day]
                
            res[i] = day
            
        return res