ALDS1_4_B 二分探索をC++で解いてみた[AIZU ONLINE JUDGE]

#include <bits/stdc++.h>
using namespace std;

bool binary_search(int S[], int n, int key) {
	int left = 0;
	int right = n;
	while (left < right) {
		int mid = (left + right) / 2;
		if (S[mid] == key) {
			return true;
		} else if (key < S[mid]) {
			right = mid;
		} else {
			left = mid + 1;
		}
	}
	return false;
}

int main() {
	int n;
	cin >> n;
	int S[n];
	for (int i = 0; i < n; i++) {
		cin >> S[i];
	}
	int q;
	cin >> q;
	int T[q];
	for (int i = 0; i < q; i++) {
		cin >> T[i];
	}

	int count = 0;
	for (int i = 0; i < q; i++) {
		if (binary_search(S, n, T[i])) {
			count++;
		}
	}

	cout << count << endl;

	return 0;
}