leetcode/java/346_Moving_Average_of_Data_Stream.java at master · cphysics/leetcode

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https://leetcode.com/problems/moving-average-from-data-stream/

Given a stream of integers and a window size, calculate the moving average of all integers in the sliding window.

Add the numbers to an array of size k with a pointer to indicate the next index to be replaced.

Track the sum and count.

Time - O(k) for constructor, O(1) for next()

Space - O(k)

public class MovingAverage {

public int sum = 0;

public int count = 0;

public int i = 0;

public int[] window;

/** Initialize your data structure here. */

public MovingAverage(int size) {

this.window = new int[size];

}

public double next(int val) {

this.sum += val - this.window[i];

this.window[i] = val;

++this.i;

this.count = Math.max(this.count, this.i);

this.i %= window.length;

return this.sum / (double) this.count;

}