题解 | #查找#

#include <cstring>
#include <iostream>
#include <algorithm>
#include <map>

using namespace std;

bool isExit(int arr[], int x) {
    int low = 0;
    int high = sizeof(arr) - 1;
    while (low <= high) {
        int mid = (low + high) / 2;
        if (arr[mid] == x)
            return true;
        else if (arr[mid] > x)
            high = mid - 1;
        else
            low = mid + 1;;
    }
    return false;
}

int main() {
    int n, m;
    int arr[100];
    map<int, int> findNum;
     cin >> n;
    for (int i = 0; i < n; i++) {
        cin >> arr[i];
        findNum[arr[i]] = i;//把数组的元素作为键，数组的下标作为值，插入到map中
    }
    sort(arr, arr + n);

    int seArr[100];

    while (scanf("%d", &m) != EOF) {
        for (int i = 0; i < m; i++) {
            scanf("%d", &seArr[i]);
            
        }
        for (int i = 0; i < m ; i++) {
            //如果没有在map中查找到seArr[i]，则findNum.find()会返回map的尾后迭代器
            if (findNum.find(seArr[i]) != findNum.end())
                cout << "YES" << endl;
            else
                cout << "NO" << endl;
        }
    }
}
// 64 位输出请用 printf("%lld")