#![allow(dead_code)]
pub fn contains_duplicate(nums: Vec<i32>) -> bool {
use std::collections::HashSet;
let mut set = HashSet::new();
for num in nums {
if set.insert(num) == false {
return true;
}
}
false
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test1() {
assert_eq!(contains_duplicate(vec![1, 2, 3, 1]), true);
}
}