17153 班级活动

⭐️难度：简单
🌟考点：2023、思维、国赛
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import java.util.Arrays;
import java.util.LinkedList;
import java.util.Queue;
import java.util.Scanner;public class Main {static int N = 100010;public static void main(String[] args) {Scanner sc = new Scanner(System.in);int n = sc.nextInt();int[] a = new int[N];int[] c = new int[N];for (int i = 0; i < n; i++) {a[i] = sc.nextInt();c[a[i]] ++;}int cnt1 = 0;int cnt2 = 0;for (int i = 0; i < c.length; i++) {if(c[i] == 1){cnt1 ++;}if(c[i] > 2){cnt2 = cnt2 + (c[i] - 2);}}System.out.println(cnt2 > cnt1 ? cnt2 : (cnt1 + cnt2) / 2);}
}