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extern crate rand;
use rand::{Rng, thread_rng, rngs::ThreadRng};
use std::collections::HashMap;
struct RandomizedSet {
rng: ThreadRng,
data: Vec<i32>,
idx_map: HashMap<i32, usize>
}
impl RandomizedSet {
fn new() -> Self {
Self {
rng: thread_rng(),
data: vec![],
idx_map: HashMap::new()
}
}
fn insert(&mut self, val: i32) -> bool {
if self.idx_map.contains_key(&val) {
return false;
}
self.idx_map.insert(val, self.data.len());
self.data.push(val);
true
}
fn remove(&mut self, val: i32) -> bool {
if self.idx_map.contains_key(&val) == false {
return false;
}
let i = self.idx_map.remove(&val).unwrap();
if i != self.data.len() - 1 {
self.data[i] = self.data[self.data.len() - 1];
(*self.idx_map.get_mut(&self.data[i]).unwrap()) = i;
}
self.data.pop();
true
}
fn get_random(&mut self) -> i32 {
if self.data.len() == 0 {
panic!(":P")
}
self.data[self.rng.gen_range(0, self.data.len())]
}
}
fn main() {
let obj = RandomizedSet::new();
let ret_1: bool = obj.insert(2);
let ret_2: bool = obj.remove(1);
let ret_3: i32 = obj.get_random();
println!("param_1 (insert 2): {}", ret_1);
println!("param_2 (remove 1): {}", ret_2);
print!("param_3 (get_random): {}", ret_3);
}
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