package com.icewei.alg.leetcode.acwing.chapter1.basicalgo2;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.StreamTokenizer;
import java.util.Arrays;

/**
 * @author icewei
 * @Description: 哈希表   acwing-ycx
 * @date 2025/2/7
 */
public class Hash {

    /*************** 840. 模拟散列表 用数组（哈西桶）+链表（数组模拟的链表）模拟散列表************/
    /*************** 这是拉链法 ************/
    /*************** 桶是用value 做索引的 ************/
    private static int N = 100010;
    private static int idx = 0;
    private static int[] h = new int[N];
    private static int[] e = new int[N];
    private static int[] ne = new int[N];

    // 有点数组模拟的单链表的add_to_head的意思，Danlianbiao.java
    private static void insert(int x) {
        int k = (x % N + N) % N;
        e[idx] = x; ne[idx] = h[k];
        h[k] = idx++;
    }

    private static boolean find(int x) {
        int k = (x % N + N) % N;
        for (int i = h[k]; i != -1; i = ne[i]) {
            if (e[i] == x) return true;
        }
        return false;
    }

    private static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    private static StreamTokenizer st = new StreamTokenizer(br);
    public static void main(String[] args) throws IOException {
        st.nextToken(); int n = (int)st.nval;
        Arrays.fill(h, -1);

        while (n-- > 0) {
            st.nextToken(); String op = st.sval;
            st.nextToken(); int x = (int)st.nval;
            if ("I".equals(op)) {
                insert(x);
            } else {
                System.out.println(find(x) ? "Yes":"No");
            }
        }
    }

    /*************** 840. 模拟散列表 简单版本，只要一个数组************/
    /*************** 这是开放寻址法法 ************/
    static class Kaifangxunzhifa {
        private static int N = 100010;
        private static int NULL_POSITION = 0x3f3f3f3f;
        private static int[] h = new int[2*N];//一般建议 2-3倍 N，冲突概率小一些

        // 返回的是x应该在的位置，可能是空位置
        private static int find(int x) {
            int k = (x % N + N) % N;
            while (h[k] != NULL_POSITION && h[k] != x) {
                k++;
                if (k == N) k = 0;
            }
            return k;
        }

        private static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        private static StreamTokenizer st = new StreamTokenizer(br);
        public static void main(String[] args) throws IOException {
            st.nextToken(); int n = (int)st.nval;
            Arrays.fill(h, NULL_POSITION);

            while (n-- > 0) {
                st.nextToken(); String op = st.sval;
                st.nextToken(); int x = (int)st.nval;
                int k = find(x);
                if ("I".equals(op)) {
                    h[k] = x;
                } else {
                    System.out.println(h[k] != NULL_POSITION ? "Yes":"No");
                }
            }
        }
    }
}