#![allow(dead_code)]
// todo: use hashmap
pub fn array_pair_sum(mut nums: Vec<i32>) -> i32 {
nums.sort();
nums.iter().step_by(2).sum()
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test1() {
let nums = vec![1, 4, 3, 2];
let res = array_pair_sum(nums);
assert_eq!(res, 4);
}
}