题解 | #定位查找#

using namespace std;

int main() {
    int n, m;
    while (cin >> n) {
        int a[n];
        for (int i = 0; i < n; ++i) {
            cin >> a[i];
        }
        cin >> m;
        int num = -1;
        for (int i = 0; i < n; ++i) {
            if (a[i] == m) {
                num = i;
                break;
            }
        }
        if (num != -1) {
            cout << num << endl;
        } else {
            cout << "No" << endl;
        }
    }

    return 0;
}