346. 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.
Implement the MovingAverage
class:
MovingAverage(int size)
Initializes the object with the size of the windowsize
.double next(int val)
Returns the moving average of the lastsize
values of the stream.
Example 1:
Input ["MovingAverage", "next", "next", "next", "next"] [[3], [1], [10], [3], [5]] Output [null, 1.0, 5.5, 4.66667, 6.0] Explanation MovingAverage movingAverage = new MovingAverage(3); movingAverage.next(1); // return 1.0 = 1 / 1 movingAverage.next(10); // return 5.5 = (1 + 10) / 2 movingAverage.next(3); // return 4.66667 = (1 + 10 + 3) / 3 movingAverage.next(5); // return 6.0 = (10 + 3 + 5) / 3
Constraints:
1 <= size <= 1000
-105 <= val <= 105
- At most
104
calls will be made tonext
.
Rust Solution
use std::collections::VecDeque;
struct MovingAverage {
queue: VecDeque<i32>,
sum: i32,
size: usize,
}
impl MovingAverage {
fn new(size: i32) -> Self {
MovingAverage {
queue: VecDeque::new(),
sum: 0,
size: size as usize,
}
}
fn next(&mut self, val: i32) -> f64 {
self.sum += val;
self.queue.push_back(val);
if self.queue.len() > self.size {
if let Some(front) = self.queue.pop_front() {
self.sum -= front;
}
}
self.sum as f64 / self.queue.len() as f64
}
}
#[test]
fn test() {
use assert_approx_eq::assert_approx_eq;
let mut m = MovingAverage::new(3);
assert_approx_eq!(m.next(1), 1f64);
assert_approx_eq!(m.next(10), 5.5f64);
assert_approx_eq!(m.next(3), 14f64 / 3f64);
assert_approx_eq!(m.next(5), 6f64);
}
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