Daily Temperatures

Problem Statement - link #

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.

Examples #

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]

Example 4:

Input: nums = [0]
Output: 1
Explanation: n = 1 since there is 1 number, so all numbers are in the range [0,1]. 1 is the missing number in the range since it does not appear in nums.

Constraints #

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

Solutions #

class Solution {
public:
    vector<int> dailyTemperatures(vector<int>& temperatures) {
      int n = temperatures.size();
      vector<int> res(n);
      stack<int> q;
      for(int i=0; i<n; i++){
        int j = temperatures[i];
        while( !q.empty() and temperatures[q.top()] < j ){
          int l = q.top();
          q.pop();
          res[l] = i - l;
        }
        q.push(i);
      }
      return res;
    }
};