백준 1744

package baekjoon.그리디;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Comparator;
import java.util.PriorityQueue;

class Main1744 {

   public static void main(String[] args) throws Exception {
      BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
      int N = Integer.parseInt(br.readLine());
      PriorityQueue<Integer> a1 = new PriorityQueue<>(Comparator.reverseOrder());
      PriorityQueue<Integer> a2 = new PriorityQueue<>();
      boolean isZero = false;

      for (int i = 0; i < N; i++) {
         int n = Integer.parseInt(br.readLine());
         if (n > 0) {
            a1.add(n);
         } else if (n < 0) {
            a2.add(n);
         } else {
            isZero = true;
         }
      }

      int ans = 0;

      while (!a1.isEmpty()) {
         if (a1.size() >=2) {
            Integer tmp1 = a1.poll();
            Integer tmp2 = a1.poll();
            if (tmp1 == 1 || tmp2 == 1) {
               ans += tmp1 + tmp2;
            } else {
               ans += tmp1 * tmp2;
            }
         } else {
            Integer tmp1 = a1.poll();
            ans += tmp1;
         }
      }
      while (!a2.isEmpty()) {
         if (a2.size() >= 2) {
            Integer tmp1 = a2.poll();
            Integer tmp2 = a2.poll();
            ans += tmp1 * tmp2;
         } else {
            int tmp1 = a2.poll();
            if (!isZero) {
               ans += tmp1;
            }
         }
      }

      System.out.println(ans);

   }
}