Daily Temperatures - Implementation

Here's the solution:

function dailyTemperatures(temperatures)
    n := length of temperatures
    answer := array of size n, all zeros
    stack := empty stack  // stores indices

    for i from 0 to n - 1
        while stack is not empty and temperatures[i] > temperatures[top of stack]
            j := pop from stack
            answer[j] := i - j
        push i onto stack

    return answer

Time: $O(n)$. Space: $O(n)$.