Daily Temperatures — LeetCode 739 Python Solution

The problem

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 ith day to get a warmer temperature. If there is no future day for which this is possible, keep answer[i] == 0 instead.

Example

Input

temperatures = [73,74,75,71,69,72,76,73]

Output

[1,1,4,2,1,1,0,0]

Python solution

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

Complexity

Pattern: Stack

When the most recent unresolved thing is the one that matters, use a stack. LeetCode 739. Daily Temperatures is filed here because LeetCode tags it Stack, which is the vocabulary this hub collects.

The stack guide has the Python template for the pattern and the 194 LeetCode problems that use it.

Related problems