739. Daily Temperatures

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# 題目敘述

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]

# 解題思路

# Solution

import java.util.Arrays;

import java.util.Stack;

class Solution {

    public int[] dailyTemperatures(int[] temperatures) {

        int n = temperatures.length;

        int[] answers = new int[n];

        Arrays.fill(answers, 0);

        Stack<Integer> s = new Stack<>();

        for(int i = 0; i < n; i++){

            while(!s.isEmpty() && temperatures[s.peek()] < temperatures[i]){

                answers[s.peek()] = i - s.pop();

            }

            s.push(i);

        }

        return answers;

     }

}

#include <vector>

#include <stack>

using namespace std;

class Solution {

 public:

  vector<int> dailyTemperatures(vector<int>& temperatures) {

    int n = temperatures.size();

    vector<int> answers(n);

    stack<int> stack;

    for(int i = 0; i < n; i++){

        while (!stack.empty() && temperatures[stack.top()] < temperatures[i])

        {

            answers[stack.top()] = i - stack.top();

            stack.pop();

        }

        stack.push(i);

    }

    return answers;

  }

};