739. Daily Temperatures

Given an array of integers temperatures represents the daily temperatures, return an array answer such that answer[i] is the number of days you have to wait after the i^th day to get a warmer temperature. If there is no future day for which this is possible, keep answer[i] == 0 instead

Array

Example 1:

Input: temperatures = [73,74,75,71,69,72,76,73]
Output: [1,1,4,2,1,1,0,0]

Example 2:

Input: temperatures = [30,40,50,60]
Output: [1,1,1,0]

Example 3:

Input: temperatures = [30,60,90]
Output: [1,1,0]

Constraints:

1 <= temperatures.length <= 10^5
30 <= temperatures[i] <= 100

Approach

Solution

class Solution:
    def dailyTemperatures(self, temperatures: List[int]) -> List[int]:
        ans = [0] * len(temperatures)
        stack = []
        for i, temp in enumerate(temperatures):
            while stack and temperatures[stack[-1]] < temp:
                prev = stack.pop()
                ans[prev] = i - prev
            stack.append(i)
        return ans