LC 739 Daily Temperatures

Implementation

// 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 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 <= temperatures.length <= 105
// 30 <= temperatures[i] <= 100

var dailyTemperatures = (arr) => {
  const n = arr.length;
  const res = new Array(n).fill(0);
  const stack = [];
  for (let i = 0; i < n; i++) {
    while (stack.length>0 && arr[i] > arr[stack[stack.length - 1]]) {
      let prevIndex = stack.pop();
      res[prevIndex] = i - prevIndex;
    }
    stack.push(i);
  }
  return res;
};

console.log(dailyTemperatures([73, 74, 75, 71, 69, 72, 76, 73]));
console.log(dailyTemperatures([30, 40, 50, 60]));
console.log(dailyTemperatures([30, 60, 90]));

Tests

// Test stub for 02.739.DailyTemperatures

describe('02.739.DailyTemperatures', () => {
  it('should have a test stub', () => {
    expect(true).toBe(true);
  });
});