rt，为什么会有RE额。。。我没搞清楚

语言：c++

# include <iostream>
# include <map>
using namespace std;

map<int, int> mp;
int a[5005];

int main() {
	int n, q;
	cin >> n >> q;
	for (int i = 1; i <= n; ++i) {
		cin >> a[i];
	}
	for (int i = 1; i <= q; ++i) {
		int l, r;
		cin >> l >> r;
		for (int j = l; j <= r; ++j) {
			++mp[a[j]];
		}
		int cnt = 0;
		for (auto kv : mp) {
			if (kv.second == 2) {
				++cnt;
			}
		}
		mp.clear();
		cout << cnt << endl;
	}

	return 0;
}

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