739. Daily Temperatures

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 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 <=&nbsp;temperatures.length <= 105

• 30 <=&nbsp;temperatures[i] <= 100

Solution

/**
 * @param {number[]} temperatures
 * @return {number[]}
 */
var dailyTemperatures = function(temperatures) {
    var stack = [];
    var res = Array(temperatures.length).fill(0);
    for (var i = 0; i < temperatures.length; i++) {
        while (stack.length && temperatures[i] > temperatures[stack[stack.length - 1]]) {
            var index = stack.pop();
            res[index] = i - index;
        }
        stack.push(i);
    }
    return res;
};

Explain:

nope.

Complexity:

• Time complexity : O(n).
• Space complexity : O(n).