蒟蒻的一个问题

#include <bits/stdc++.h>
using namespace std;
int a[100010];
int main() {
    int n;
    scanf("%d", &n);
    for (int i = 1; i <= n; i++) scanf("%d", a + i);
    int q, k;
    scanf("%d", &q);
    while (q--) {
        scanf("%d", &k);
        int l = 1, r = n, mid;
        while (l < r) {
            mid = l + r >> 1;
            if (a[mid] < k)
                l = mid + 1;
            else
                r = mid;
        }
        if (abs(a[l] - k) < abs(a[l - 1] - k)) {
            printf("%d\n", a[l]);
        }

        else
            printf("%d\n", a[l - 1]);
    }
    return 0;
}