20240723 Finished

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jackfiled 2024-07-23 11:42:36 +08:00
parent 89cd879900
commit ca02539332
2 changed files with 102 additions and 1 deletions

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@ -181,4 +181,5 @@ mod p34_find_first_and_last_position_of_element_in_sorted_array;
mod p153_find_minimum_in_rotated_sorted_array;
mod p215_kth_largest_element_in_an_array;
mod p502_ipo;
mod p373_find_k_pairs_with_smallest_sums;
mod p373_find_k_pairs_with_smallest_sums;
mod p295_find_median_from_data_stream;

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@ -0,0 +1,100 @@
/**
* [295] Find Median from Data Stream
*/
pub struct Solution {}
// submission codes start here
use std::{cmp::Reverse, collections::BinaryHeap};
#[derive(Debug)]
struct MedianFinder {
left: BinaryHeap<i32>,
right: BinaryHeap<Reverse<i32>>
}
/**
* `&self` means the method takes an immutable reference.
* If you need a mutable reference, change it to `&mut self` instead.
*/
impl MedianFinder {
fn new() -> Self {
Self {
left: BinaryHeap::new(),
right: BinaryHeap::new()
}
}
fn add_num(&mut self, num: i32) {
// 保证如下的状态
// left.len = right.len + 1
// left.len = right.len
if self.left.len() > self.right.len() {
// 此时左边必然有数
let left_peek = *self.left.peek().unwrap();
if num >= left_peek {
self.right.push(Reverse(num))
} else {
self.right.push(Reverse(left_peek));
self.left.pop();
self.left.push(num);
}
} else {
// 判空
if self.left.is_empty() {
self.left.push(num);
} else {
// 此时必然两端都有数
let right_peek = self.right.peek().unwrap().0;
if num <= right_peek {
self.left.push(num);
} else {
self.left.push(right_peek);
self.right.pop();
self.right.push(Reverse(num));
}
}
}
}
fn find_median(&self) -> f64 {
return if self.left.len() == self.right.len() {
(*self.left.peek().unwrap() as f64 + self.right.peek().unwrap().0 as f64) / 2f64
} else {
*self.left.peek().unwrap() as f64
}
}
}
/**
* Your MedianFinder object will be instantiated and called as such:
* let obj = MedianFinder::new();
* obj.add_num(num);
* let ret_2: f64 = obj.find_median();
*/
// submission codes end
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_295() {
let mut finder = MedianFinder::new();
finder.add_num(1);
finder.add_num(2);
assert_eq!(1.5, finder.find_median());
finder.add_num(3);
finder = dbg!(finder);
assert_eq!(2f64, finder.find_median());
}
}