LintCode 868. Maximum Average Subarray_单调队列子数组的最大平均值 ii-优快云博客

本文介绍了一种使用滑动窗口算法解决寻找给定长度的最大平均子数组的问题。通过示例说明了如何实现这一算法，包括初始化窗口、遍历数组并更新窗口和最大平均值的过程。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

Maximum Average Subarray

Given an array consisting of n integers, find the contiguous subarray of given length k that has the maximum average value. You need to output the maximum average value.

Example
Example1

Input: nums = [1,12,-5,-6,50,3] and k = 4
Output: 12.75
Explanation:
Maximum average is (12-5-6+50)/4 = 51/4 = 12.75
Example2

Input: nums = [4,2,1,3,3] and k = 2
Output: 3.00
Explanation:
Maximum average is (3+3)/2 = 6/2 = 3.00
Notice
1 <= k <= n <= 30,000.
Elements of the given array will be in the range [-10,000, 10,000].

思路：滑动窗口。
记得maxResult初值设为numeric_limits::lowest();
要include。

代码如下：

#include <limits>

class Solution {
public:
    /**
     * @param nums: an array
     * @param k: an integer
     * @return: the maximum average value
     */
    double findMaxAverage(vector<int> &nums, int k) {
        int len = nums.size();
        if (len == 0 || len < k) return 0.0;
        
        double result = 0.0;
        double maxResult = numeric_limits<double>::lowest();
        
        double windowSum = 0;
        
        for (int i = 0; i < len; ++i) {
            windowSum += nums[i];
            if (i >= k) windowSum -= nums[i - k];
            maxResult = max(maxResult, windowSum);
        }
        
        return maxResult / k;
    }
};