问题 C: 查找

#include <cstdio>
#include <vector>
#include <algorithm>

using namespace std;

bool b_search(const vector<int> &a, int x) {

    int left = 0, right = a.size() - 1;

    while (left <= right) {
        int mid = left + (right - left) / 2;

        if (a[mid] == x) return true;
        if (a[mid] < x) {
            left = mid + 1;
        } else {
            right = mid - 1;
        }
    }

    return false;

}

int main() {

    int n;
    while (scanf(" %d", &n) != EOF) {
        vector<int> a;
        for (int i = 0; i < n; ++i) {
            int temp;
            scanf("%d", &temp);
            a.push_back(temp);
        }

        sort(a.begin(),a.end());

        int m;
        scanf("%d", &m);

        for (int j = 0; j < m; ++j) {
            int temp;
            scanf("%d", &temp);
            if (b_search(a, temp)) printf("YES\n");
            else printf("NO\n");
        }

    }
    return 0;
}