/*
 * @lc app=leetcode id=922 lang=rust
 *
 * [922] Sort Array By Parity II
 *
 * https://leetcode.com/problems/sort-array-by-parity-ii/description/
 *
 * algorithms
 * Easy (68.02%)
 * Total Accepted:    76.3K
 * Total Submissions: 112.1K
 * Testcase Example:  '[4,2,5,7]'
 *
 * Given an array A of non-negative integers, half of the integers in A are
 * odd, and half of the integers are even.
 * 
 * Sort the array so that whenever A[i] is odd, i is odd; and whenever A[i] is
 * even, i is even.
 * 
 * You may return any answer array that satisfies this condition.
 * 
 * 
 * 
 * Example 1:
 * 
 * 
 * Input: [4,2,5,7]
 * Output: [4,5,2,7]
 * Explanation: [4,7,2,5], [2,5,4,7], [2,7,4,5] would also have been
 * accepted.
 * 
 * 
 * 
 * 
 * Note:
 * 
 * 
 * 2 <= A.length <= 20000
 * A.length % 2 == 0
 * 0 <= A[i] <= 1000
 * 
 * 
 * 
 * 
 * 
 */
impl Solution {
    pub fn sort_array_by_parity_ii(a: Vec<i32>) -> Vec<i32> {
        let mut res = vec![0; a.len()];
        let mut i = 0; 
        let mut j = 1; 
        for n in a{
            if n % 2 == 0 {
                res[i] = n; 
                i += 2; 
            } else {
                res[j] = n; 
                j += 2;
            }
        }
        res 
    }
}


// pub structSolution; 
use std::collections::HashMap;
use std::collections::HashSet;
use std::fmt::Debug;
use std::hash::Hash;
use std::iter::FromIterator;
use std::collections::VecDeque; 

#[allow(dead_code)]
pub fn print_map<K: Debug + Eq + Hash, V: Debug>(map: &HashMap<K, V>) {
    for (k, v) in map.iter() {
        println!("{:?}: {:?}", k, v);
    }
}

#[allow(dead_code)]
pub fn say_vec(nums: Vec<i32>){
	println!("{:?}", nums);
}

#[allow(dead_code)]
pub fn char_frequency(s: String) -> HashMap<char, i32> {
    let mut res:HashMap<char, i32> = HashMap::new(); 
    for c in s.chars(){
        *res.entry(c).or_insert(0) += 1;
    }
    res 
}

#[allow(dead_code)]
pub fn vec_counter(arr: Vec<i32>) -> HashMap<i32, i32> {
    let mut c = HashMap::new(); 
    for n in arr { *c.entry(n).or_insert(0) += 1; }
    c 
}

#[allow(dead_code)]
pub fn vec_to_hashset(arr: Vec<i32>) -> HashSet<i32> {
   HashSet::from_iter(arr.iter().cloned())
}